target sdk 35

Used separate threads for reading and writing, enhancing concurrency and performance.

Note: before was possible to start `SerialInputOutputManager` with `Executors.newSingleThreadExecutor().submit(ioManager)`. Now you have to use `ioManager.start()`

.github/workflows/build.yml

@@ -0,0 +1,17 @@
+name: build
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/setup-java@v3
+      with:
+        distribution: 'temurin'
+        java-version: '17'
+    - name: Build with Gradle
+      run: ./gradlew assembleDebug

.gitignore

@@ -21,6 +21,7 @@ build/
 .idea/workspace.xml
 .idea/tasks.xml
 .idea/dictionaries
+.idea/markdown-navigator*.xml
 
 # Sensitive or high-churn files:
 .idea/dataSources.ids
@@ -32,10 +33,11 @@ build/
 # Gradle:
 .idea/gradle.xml
 .idea/libraries
+.idea/jarRepositories.xml
 
 # Eclipse/Android/Misc
 .metadata/
 local.properties
 *.DS_Store
 proguard/
-
+jacoco.exec

.idea/.gitignore

@@ -2,3 +2,8 @@ caches
 codeStyles
 libraries
 workspace.xml
+androidTestResultsUserPreferences.xml
+appInsightsSettings.xml
+deploymentTargetDropDown.xml
+deploymentTargetSelector.xml
+other.xml

.idea/AndroidProjectSystem.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="AndroidProjectSystem">
+    <option name="providerId" value="com.android.tools.idea.GradleProjectSystem" />
+  </component>
+</project>

.idea/compiler.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <bytecodeTargetLevel target="21" />
+  </component>
+</project>

.idea/misc.xml

@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="NullableNotNullManager">
-    <option name="myDefaultNullable" value="android.support.annotation.Nullable" />
-    <option name="myDefaultNotNull" value="android.support.annotation.NonNull" />
+    <option name="myDefaultNullable" value="androidx.annotation.Nullable" />
+    <option name="myDefaultNotNull" value="androidx.annotation.NonNull" />
     <option name="myNullables">
       <value>
-        <list size="7">
+        <list size="18">
           <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.Nullable" />
           <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nullable" />
           <item index="2" class="java.lang.String" itemvalue="javax.annotation.CheckForNull" />
@@ -13,23 +14,45 @@
           <item index="4" class="java.lang.String" itemvalue="android.support.annotation.Nullable" />
           <item index="5" class="java.lang.String" itemvalue="androidx.annotation.Nullable" />
           <item index="6" class="java.lang.String" itemvalue="androidx.annotation.RecentlyNullable" />
+          <item index="7" class="java.lang.String" itemvalue="android.annotation.Nullable" />
+          <item index="8" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.Nullable" />
+          <item index="9" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableDecl" />
+          <item index="10" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableType" />
+          <item index="11" class="java.lang.String" itemvalue="com.android.annotations.Nullable" />
+          <item index="12" class="java.lang.String" itemvalue="org.eclipse.jdt.annotation.Nullable" />
+          <item index="13" class="java.lang.String" itemvalue="io.reactivex.annotations.Nullable" />
+          <item index="14" class="java.lang.String" itemvalue="io.reactivex.rxjava3.annotations.Nullable" />
+          <item index="15" class="java.lang.String" itemvalue="org.jspecify.nullness.Nullable" />
+          <item index="16" class="java.lang.String" itemvalue="jakarta.annotation.Nullable" />
+          <item index="17" class="java.lang.String" itemvalue="org.jspecify.annotations.Nullable" />
         </list>
       </value>
     </option>
     <option name="myNotNulls">
       <value>
-        <list size="6">
+        <list size="17">
           <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.NotNull" />
           <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nonnull" />
           <item index="2" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.NonNull" />
           <item index="3" class="java.lang.String" itemvalue="android.support.annotation.NonNull" />
           <item index="4" class="java.lang.String" itemvalue="androidx.annotation.NonNull" />
           <item index="5" class="java.lang.String" itemvalue="androidx.annotation.RecentlyNonNull" />
+          <item index="6" class="java.lang.String" itemvalue="android.annotation.NonNull" />
+          <item index="7" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.NonNull" />
+          <item index="8" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NonNullDecl" />
+          <item index="9" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NonNullType" />
+          <item index="10" class="java.lang.String" itemvalue="com.android.annotations.NonNull" />
+          <item index="11" class="java.lang.String" itemvalue="org.eclipse.jdt.annotation.NonNull" />
+          <item index="12" class="java.lang.String" itemvalue="io.reactivex.annotations.NonNull" />
+          <item index="13" class="java.lang.String" itemvalue="io.reactivex.rxjava3.annotations.NonNull" />
+          <item index="14" class="java.lang.String" itemvalue="jakarta.annotation.Nonnull" />
+          <item index="15" class="java.lang.String" itemvalue="org.jspecify.nullness.NonNull" />
+          <item index="16" class="java.lang.String" itemvalue="org.jspecify.annotations.NonNull" />
         </list>
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="jbr-21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

.idea/modules.xml

@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/usb-serial-for-android.iml" filepath="$PROJECT_DIR$/usb-serial-for-android.iml" />
-      <module fileurl="file://$PROJECT_DIR$/usbSerialExamples/usbSerialExamples.iml" filepath="$PROJECT_DIR$/usbSerialExamples/usbSerialExamples.iml" />
-      <module fileurl="file://$PROJECT_DIR$/usbSerialForAndroid/usbSerialForAndroid.iml" filepath="$PROJECT_DIR$/usbSerialForAndroid/usbSerialForAndroid.iml" />
-    </modules>
-  </component>
-</project>

.idea/runConfigurations.xml

@@ -3,9 +3,14 @@
   <component name="RunConfigurationProducerService">
     <option name="ignoredProducers">
       <set>
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
+        <option value="com.intellij.execution.junit.AbstractAllInDirectoryConfigurationProducer" />
+        <option value="com.intellij.execution.junit.AllInPackageConfigurationProducer" />
+        <option value="com.intellij.execution.junit.PatternConfigurationProducer" />
+        <option value="com.intellij.execution.junit.TestInClassConfigurationProducer" />
+        <option value="com.intellij.execution.junit.UniqueIdConfigurationProducer" />
+        <option value="com.intellij.execution.junit.testDiscovery.JUnitTestDiscoveryConfigurationProducer" />
+        <option value="org.jetbrains.kotlin.idea.junit.KotlinJUnitRunConfigurationProducer" />
+        <option value="org.jetbrains.kotlin.idea.junit.KotlinPatternConfigurationProducer" />
       </set>
     </option>
   </component>

CHANGELOG.txt

@@ -1,4 +1,7 @@
-Current Version (in development)
+For recent changelog look here:
+  * https://github.com/mik3y/usb-serial-for-android/releases
+
+v0.2.0 (unreleased)
   * Gradle, Android Studio support.
   * New driver: CP2102 (thanks Ducky).
   * New prober support: LUFA Virtual Serial, Leaflabs Maple, Teensyduino.

LICENSE.txt

@@ -1,456 +1,22 @@
-                  GNU LESSER GENERAL PUBLIC LICENSE
-                       Version 2.1, February 1999
+MIT License
 
- Copyright (C) 1991, 1999 Free Software Foundation, Inc.
- 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
+Copyright (c) 2011-2013 Google Inc.
+Copyright (c) 2013 Mike Wakerly
 
-[This is the first released version of the Lesser GPL.  It also counts
- as the successor of the GNU Library Public License, version 2, hence
- the version number 2.1.]
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-                            Preamble
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
-Licenses are intended to guarantee your freedom to share and change
-free software--to make sure the software is free for all its users.
-
-  This license, the Lesser General Public License, applies to some
-specially designated software packages--typically libraries--of the
-Free Software Foundation and other authors who decide to use it.  You
-can use it too, but we suggest you first think carefully about whether
-this license or the ordinary General Public License is the better
-strategy to use in any particular case, based on the explanations below.
-
-  When we speak of free software, we are referring to freedom of use,
-not price.  Our General Public Licenses are designed to make sure that
-you have the freedom to distribute copies of free software (and charge
-for this service if you wish); that you receive source code or can get
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-Such new versions will be similar in spirit to the present version,
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-
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+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -1,5 +1,7 @@
+[![Actions Status](https://github.com/mik3y/usb-serial-for-android/workflows/build/badge.svg)](https://github.com/mik3y/usb-serial-for-android/actions)
 [![Jitpack](https://jitpack.io/v/mik3y/usb-serial-for-android.svg)](https://jitpack.io/#mik3y/usb-serial-for-android)
-[![Codacy](https://api.codacy.com/project/badge/Grade/4d528e82e35d42d49f659e9b93a9c77d)](https://www.codacy.com/manual/kai-morich/usb-serial-for-android-mik3y?utm_source=github.com&utm_medium=referral&utm_content=mik3y/usb-serial-for-android&utm_campaign=Badge_Grade)
+[![Codacy](https://app.codacy.com/project/badge/Grade/ef799bba8a7343818af0a90eba3ecb46)](https://app.codacy.com/gh/kai-morich/usb-serial-for-android-mik3y/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade)
+[![codecov](https://codecov.io/gh/mik3y/usb-serial-for-android/branch/master/graph/badge.svg)](https://codecov.io/gh/mik3y/usb-serial-for-android)
 
 # usb-serial-for-android
 
@@ -9,8 +11,7 @@ Android, using the
 available since Android 3.1 and working reliably since Android 4.2.
 
 No root access, ADK, or special kernel drivers are required; all drivers are implemented in
-Java.  You get a raw serial port with `read()`, `write()`, and other basic
-functions for use with your own protocols.
+Java.  You get a raw serial port with `read()`, `write()`, and [other functions](https://github.com/mik3y/usb-serial-for-android/wiki/FAQ#Feature_Matrix) for use with your own protocols.
 
 ## Quick Start
 
@@ -25,73 +26,99 @@ allprojects {
     }
 }
 ```
-Add library to dependencies
+
+Starting with gradle 6.8 you can alternatively add jitpack.io repository to your settings.gradle:
 ```gradle
-dependencies {
-    implementation 'com.github.mik3y:usb-serial-for-android:Tag'
+dependencyResolutionManagement {
+    repositories {
+        ...
+        maven { url 'https://jitpack.io' }
+    }
 }
 ```
 
-**2.** Copy [device_filter.xml](https://github.com/mik3y/usb-serial-for-android/blob/master/usbSerialExamples/src/main/res/xml/device_filter.xml) to your project's `res/xml/` directory.
+If using gradle kotlin  use line
+```gradle.kts
+        maven(url = "https://jitpack.io")
+```
 
-**3.** Configure your `AndroidManifest.xml` to notify your app when a device is attached (see [Android USB Host documentation](http://developer.android.com/guide/topics/connectivity/usb/host.html#discovering-d) for help).
+Add library to dependencies
+```gradle
+dependencies {
+    implementation 'com.github.mik3y:usb-serial-for-android:3.9.0'
+}
+```
+
+**2.** If the app should be notified when a device is attached, add 
+[device_filter.xml](https://github.com/mik3y/usb-serial-for-android/blob/master/usbSerialExamples/src/main/res/xml/device_filter.xml) 
+to your project's `res/xml/` directory and configure in your `AndroidManifest.xml`.
 
 ```xml
 <activity
     android:name="..."
     ...>
-  <intent-filter>
-    <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
-  </intent-filter>
-  <meta-data
-      android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
-      android:resource="@xml/device_filter" />
+    <intent-filter>
+        <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
+    </intent-filter>
+    <meta-data
+        android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
+        android:resource="@xml/device_filter" />
 </activity>
 ```
 
-**4.** Use it! Example code snippet:
+**3.** Use it! Example code snippet:
 
+open device:
 ```java
-// Find all available drivers from attached devices.
-UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
-List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
-if (availableDrivers.isEmpty()) {
-  return;
-}
+    // Find all available drivers from attached devices.
+    UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
+    List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
+    if (availableDrivers.isEmpty()) {
+        return;
+    }
 
-// Open a connection to the first available driver.
-UsbSerialDriver driver = availableDrivers.get(0);
-UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
-if (connection == null) {
-  // You probably need to call UsbManager.requestPermission(driver.getDevice(), ..)
-  return;
-}
+    // Open a connection to the first available driver.
+    UsbSerialDriver driver = availableDrivers.get(0);
+    UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
+    if (connection == null) {
+        // add UsbManager.requestPermission(driver.getDevice(), ..) handling here
+        return;
+    }
 
-// Read some data! Most have just one port (port 0).
-UsbSerialPort port = driver.getPorts().get(0);
-try {
-  port.open(connection);
-  port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
-
-  byte buffer[] = new byte[16];
-  int numBytesRead = port.read(buffer, 1000);
-  Log.d(TAG, "Read " + numBytesRead + " bytes.");
-} catch (IOException e) {
-  // Deal with error.
-} finally {
-  port.close();
+    UsbSerialPort port = driver.getPorts().get(0); // Most devices have just one port (port 0)
+    port.open(connection);
+    port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
+```
+then use direct read/write
+```java
+    port.write(request, WRITE_WAIT_MILLIS);
+    len = port.read(response, READ_WAIT_MILLIS);
+```
+or direct write + event driven read:
+```java
+    usbIoManager = new SerialInputOutputManager(usbSerialPort, this);
+    usbIoManager.start();
+    ...
+    port.write("hello".getBytes(), WRITE_WAIT_MILLIS);
+    
+@Override
+public void onNewData(byte[] data) {
+    runOnUiThread(() -> { textView.append(new String(data)); });
 }
 ```
+and finally:
+```java
+    port.close();
+```
 
-For a simple example, see the
-[UsbSerialExamples project](https://github.com/mik3y/usb-serial-for-android/blob/master/usbSerialExamples)
-in git, which is a simple application for reading and showing serial data.
+For a simple example, see
+[UsbSerialExamples](https://github.com/mik3y/usb-serial-for-android/blob/master/usbSerialExamples)
+folder in this project.
 
-For a more complete example, see separate github project 
-[SimpleUsbTerminal](https://github.com/kai-morich/SimpleUsbTerminal)
-
-A [simple Arduino application](https://github.com/mik3y/usb-serial-for-android/blob/master/arduino)
-is also available which can be used for testing.
+See separate github project [SimpleUsbTerminal](https://github.com/kai-morich/SimpleUsbTerminal) 
+for a more complete example with:
+* Background service to stay connected while the app is not visible or rotating
+* Flow control 
 
 ## Probing for Unrecognized Devices
 
@@ -103,22 +130,23 @@ new device or for one using a custom VID/PID pair.
 UsbSerialProber is a class to help you find and instantiate compatible
 UsbSerialDrivers from the tree of connected UsbDevices.  Normally, you will use
 the default prober returned by ``UsbSerialProber.getDefaultProber()``, which
-uses the built-in list of well-known VIDs and PIDs that are supported by our
-drivers.
+uses USB interface types and the built-in list of well-known VIDs and PIDs that
+are supported by our drivers.
 
 To use your own set of rules, create and use a custom prober:
 
 ```java
-// Probe for our custom CDC devices, which use VID 0x1234
-// and PIDS 0x0001 and 0x0002.
+// Probe for our custom FTDI device, which use VID 0x1234 and PID 0x0001 and 0x0002.
 ProbeTable customTable = new ProbeTable();
-customTable.addProduct(0x1234, 0x0001, CdcAcmSerialDriver.class);
-customTable.addProduct(0x1234, 0x0002, CdcAcmSerialDriver.class);
+customTable.addProduct(0x1234, 0x0001, FtdiSerialDriver.class);
+customTable.addProduct(0x1234, 0x0002, FtdiSerialDriver.class);
 
 UsbSerialProber prober = new UsbSerialProber(customTable);
 List<UsbSerialDriver> drivers = prober.findAllDrivers(usbManager);
 // ...
 ```
+*Note*: as of v3.5.0 this library detects CDC/ACM devices by USB interface types instead of fixed VID+PID,
+so custom probers are typically not required any more for CDC/ACM devices.
 
 Of course, nothing requires you to use UsbSerialProber at all: you can
 instantiate driver classes directly if you know what you're doing; just supply
@@ -126,35 +154,26 @@ a compatible UsbDevice.
 
 ## Compatible Devices
 
-This library supports USB to serial converter chips:
-* FTDI FT232, FT2232, ...
+This library supports USB to serial converter chips with specific drivers
+* FTDI FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
 * Prolific PL2303
-* Silabs CP2102, CP2105, ...
-* Qinheng CH340
+* Silabs CP2102, CP210*
+* Qinheng CH340, CH341A
 
-and devices implementing the CDC/ACM protocol like
+some other device specific drivers
+* GsmModem devices, e.g. for Unisoc based Fibocom GSM modems
+* Chrome OS CCD (Closed Case Debugging)
+
+and devices implementing the generic CDC/ACM protocol like
+* Qinheng CH9102
+* Microchip MCP2221
 * Arduino using ATmega32U4
 * Digispark using V-USB software USB
-* BBC micro:bit using ARM mbed DAPLink firmware
 * ...
 
-## Author, License, and Copyright
-
-usb-serial-for-android is written and maintained by *mike wakerly* and *kai morich*
-
-This library is licensed under *LGPL Version 2.1*.  Please see LICENSE.txt for the
-complete license.
-
-Copyright 2011-2012, Google Inc. All Rights Reserved.
-
-Portions of this library are based on [libftdi](http://www.intra2net.com/en/developer/libftdi).
-Please see FtdiSerialDriver.java for more information.
-
 ## Help & Discussion
 
-For common problems, see the
-[Troubleshooting](https://github.com/mik3y/usb-serial-for-android/wiki/Troubleshooting)
-wiki page.
+For common problems, see the [FAQ](https://github.com/mik3y/usb-serial-for-android/wiki/FAQ) wiki page.
 
 Are you using the library? Add your project to 
 [ProjectsUsingUsbSerialForAndroid](https://github.com/mik3y/usb-serial-for-android/wiki/Projects-Using-usb-serial-for-android).

build.gradle

@@ -2,17 +2,17 @@
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:8.9.1'
     }
 }
 
 allprojects {
     repositories {
-        jcenter()
+        mavenCentral()
         google()
     }
 }

codecov.yml

@@ -0,0 +1,5 @@
+codecov:
+  max_report_age: off
+  require_ci_to_pass: no
+  notify:
+    wait_for_ci: no

gradle.properties

@@ -0,0 +1,3 @@
+android.enableJetifier=true
+android.useAndroidX=true
+android.defaults.buildfeatures.buildconfig=true

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Sun Oct 06 09:46:24 CEST 2019
+#Tue Oct 13 21:20:09 CEST 2020
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-all.zip

jitpack.yml

@@ -0,0 +1,4 @@
+jdk:
+  - openjdk17
+install:
+  - ./gradlew :usbSerialForAndroid:publishToMavenLocal

test/arduino_leonardo_bridge_castrated_cdc/CDC.cpp

@@ -0,0 +1,303 @@
+
+
+/* Copyright (c) 2011, Peter Barrett  
+**  
+** Permission to use, copy, modify, and/or distribute this software for  
+** any purpose with or without fee is hereby granted, provided that the  
+** above copyright notice and this permission notice appear in all copies.  
+** 
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
+** SOFTWARE.  
+*/
+
+#include "USBCore.h" // kai:added
+#include "USBAPI.h"
+#include <avr/wdt.h>
+#include <util/atomic.h>
+
+#if defined(USBCON)
+
+typedef struct
+{
+	u32	dwDTERate;
+	u8	bCharFormat;
+	u8 	bParityType;
+	u8 	bDataBits;
+	u8	lineState;
+} LineInfo;
+
+static volatile LineInfo _usbLineInfo = { 57600, 0x00, 0x00, 0x00, 0x00 };
+static volatile int32_t breakValue = -1;
+
+static u8 wdtcsr_save;
+
+#define WEAK __attribute__ ((weak))
+
+extern const CDCDescriptor _cdcInterface PROGMEM;
+const CDCDescriptor _cdcInterface =
+{
+	D_IAD(0,2,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,1),
+
+	//	CDC communication interface
+	D_INTERFACE(CDC_ACM_INTERFACE,3,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,0), // kai
+	D_CDCCS(CDC_HEADER,0x10,0x01),								// Header (1.10 bcd)
+	D_CDCCS(CDC_CALL_MANAGEMENT,1,1),							// Device handles call management (not)
+	D_CDCCS4(CDC_ABSTRACT_CONTROL_MANAGEMENT,6),				// SET_LINE_CODING, GET_LINE_CODING, SET_CONTROL_LINE_STATE supported
+	D_CDCCS(CDC_UNION,CDC_ACM_INTERFACE,CDC_DATA_INTERFACE),	// Communication interface is master, data interface is slave 0
+	D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_ACM),USB_ENDPOINT_TYPE_INTERRUPT,0x10,0x40),
+
+	//	CDC data interface
+	//D_INTERFACE(CDC_DATA_INTERFACE,2,CDC_DATA_INTERFACE_CLASS,0,0), // kai:removed
+	D_ENDPOINT(USB_ENDPOINT_OUT(CDC_ENDPOINT_OUT),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0),
+	D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_IN ),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0)
+};
+
+bool isLUFAbootloader()
+{
+	return pgm_read_word(FLASHEND - 1) == NEW_LUFA_SIGNATURE;
+}
+
+int CDC_GetInterface(u8* interfaceNum)
+{
+	interfaceNum[0] += 1;	// kai
+	return USB_SendControl(TRANSFER_PGM,&_cdcInterface,sizeof(_cdcInterface));
+}
+
+bool CDC_Setup(USBSetup& setup)
+{
+	u8 r = setup.bRequest;
+	u8 requestType = setup.bmRequestType;
+
+	if (REQUEST_DEVICETOHOST_CLASS_INTERFACE == requestType)
+	{
+		if (CDC_GET_LINE_CODING == r)
+		{
+			USB_SendControl(0,(void*)&_usbLineInfo,7);
+			return true;
+		}
+	}
+
+	if (REQUEST_HOSTTODEVICE_CLASS_INTERFACE == requestType)
+	{
+		if (CDC_SEND_BREAK == r)
+		{
+			breakValue = ((uint16_t)setup.wValueH << 8) | setup.wValueL;
+		}
+
+		if (CDC_SET_LINE_CODING == r)
+		{
+			USB_RecvControl((void*)&_usbLineInfo,7);
+		}
+
+		if (CDC_SET_CONTROL_LINE_STATE == r)
+		{
+			_usbLineInfo.lineState = setup.wValueL;
+
+			// auto-reset into the bootloader is triggered when the port, already 
+			// open at 1200 bps, is closed.  this is the signal to start the watchdog
+			// with a relatively long period so it can finish housekeeping tasks
+			// like servicing endpoints before the sketch ends
+
+			uint16_t magic_key_pos = MAGIC_KEY_POS;
+
+// If we don't use the new RAMEND directly, check manually if we have a newer bootloader.
+// This is used to keep compatible with the old leonardo bootloaders.
+// You are still able to set the magic key position manually to RAMEND-1 to save a few bytes for this check.
+#if MAGIC_KEY_POS != (RAMEND-1)
+			// For future boards save the key in the inproblematic RAMEND
+			// Which is reserved for the main() return value (which will never return)
+			if (isLUFAbootloader()) {
+				// horray, we got a new bootloader!
+				magic_key_pos = (RAMEND-1);
+			}
+#endif
+
+			// We check DTR state to determine if host port is open (bit 0 of lineState).
+			if (1200 == _usbLineInfo.dwDTERate && (_usbLineInfo.lineState & 0x01) == 0)
+			{
+#if MAGIC_KEY_POS != (RAMEND-1)
+				// Backup ram value if its not a newer bootloader and it hasn't already been saved.
+				// This should avoid memory corruption at least a bit, not fully
+				if (magic_key_pos != (RAMEND-1) && *(uint16_t *)magic_key_pos != MAGIC_KEY) {
+					*(uint16_t *)(RAMEND-1) = *(uint16_t *)magic_key_pos;
+				}
+#endif
+				// Store boot key
+				*(uint16_t *)magic_key_pos = MAGIC_KEY;
+				// Save the watchdog state in case the reset is aborted.
+				wdtcsr_save = WDTCSR;
+				wdt_enable(WDTO_120MS);
+			}
+			else if (*(uint16_t *)magic_key_pos == MAGIC_KEY)
+			{
+				// Most OSs do some intermediate steps when configuring ports and DTR can
+				// twiggle more than once before stabilizing.
+				// To avoid spurious resets we set the watchdog to 120ms and eventually
+				// cancel if DTR goes back high.
+				// Cancellation is only done if an auto-reset was started, which is
+				// indicated by the magic key having been set.
+
+				wdt_reset();
+				// Restore the watchdog state in case the sketch was using it.
+				WDTCSR |= (1<<WDCE) | (1<<WDE);
+				WDTCSR = wdtcsr_save;
+#if MAGIC_KEY_POS != (RAMEND-1)
+				// Restore backed up (old bootloader) magic key data
+				if (magic_key_pos != (RAMEND-1)) {
+					*(uint16_t *)magic_key_pos = *(uint16_t *)(RAMEND-1);
+				} else
+#endif
+				{
+				// Clean up RAMEND key
+					*(uint16_t *)magic_key_pos = 0x0000;
+				}
+			}
+		}
+		return true;
+	}
+	return false;
+}
+
+
+void Serial_::begin(unsigned long /* baud_count */)
+{
+	peek_buffer = -1;
+}
+
+void Serial_::begin(unsigned long /* baud_count */, byte /* config */)
+{
+	peek_buffer = -1;
+}
+
+void Serial_::end(void)
+{
+}
+
+int Serial_::available(void)
+{
+	if (peek_buffer >= 0) {
+		return 1 + USB_Available(CDC_RX);
+	}
+	return USB_Available(CDC_RX);
+}
+
+int Serial_::peek(void)
+{
+	if (peek_buffer < 0)
+		peek_buffer = USB_Recv(CDC_RX);
+	return peek_buffer;
+}
+
+int Serial_::read(void)
+{
+	if (peek_buffer >= 0) {
+		int c = peek_buffer;
+		peek_buffer = -1;
+		return c;
+	}
+	return USB_Recv(CDC_RX);
+}
+
+int Serial_::availableForWrite(void)
+{
+	return USB_SendSpace(CDC_TX);
+}
+
+void Serial_::flush(void)
+{
+	USB_Flush(CDC_TX);
+}
+
+size_t Serial_::write(uint8_t c)
+{
+	return write(&c, 1);
+}
+
+size_t Serial_::write(const uint8_t *buffer, size_t size)
+{
+	/* only try to send bytes if the high-level CDC connection itself 
+	 is open (not just the pipe) - the OS should set lineState when the port
+	 is opened and clear lineState when the port is closed.
+	 bytes sent before the user opens the connection or after
+	 the connection is closed are lost - just like with a UART. */
+	
+	// TODO - ZE - check behavior on different OSes and test what happens if an
+	// open connection isn't broken cleanly (cable is yanked out, host dies
+	// or locks up, or host virtual serial port hangs)
+	if (_usbLineInfo.lineState > 0)	{
+		int r = USB_Send(CDC_TX,buffer,size);
+		if (r > 0) {
+			return r;
+		} else {
+			setWriteError();
+			return 0;
+		}
+	}
+	setWriteError();
+	return 0;
+}
+
+// This operator is a convenient way for a sketch to check whether the
+// port has actually been configured and opened by the host (as opposed
+// to just being connected to the host).  It can be used, for example, in 
+// setup() before printing to ensure that an application on the host is
+// actually ready to receive and display the data.
+// We add a short delay before returning to fix a bug observed by Federico
+// where the port is configured (lineState != 0) but not quite opened.
+Serial_::operator bool() {
+	bool result = false;
+	if (_usbLineInfo.lineState > 0) 
+		result = true;
+	delay(10);
+	return result;
+}
+
+unsigned long Serial_::baud() {
+	// Disable interrupts while reading a multi-byte value
+	uint32_t baudrate;
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		baudrate =  _usbLineInfo.dwDTERate;
+	}
+	return baudrate;
+}
+
+uint8_t Serial_::stopbits() {
+	return _usbLineInfo.bCharFormat;
+}
+
+uint8_t Serial_::paritytype() {
+	return _usbLineInfo.bParityType;
+}
+
+uint8_t Serial_::numbits() {
+	return _usbLineInfo.bDataBits;
+}
+
+bool Serial_::dtr() {
+	return _usbLineInfo.lineState & 0x1;
+}
+
+bool Serial_::rts() {
+	return _usbLineInfo.lineState & 0x2;
+}
+
+int32_t Serial_::readBreak() {
+	int32_t ret;
+	// Disable IRQs while reading and clearing breakValue to make
+	// sure we don't overwrite a value just set by the ISR.
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		ret = breakValue;
+		breakValue = -1;
+	}
+	return ret;
+}
+
+Serial_ Serial;
+
+#endif /* if defined(USBCON) */

test/arduino_leonardo_bridge_castrated_cdc/README.md

@@ -0,0 +1,8 @@
+## castrated CDC test (single interface with 3 endpoints)
+
+As mentioned [here](https://arduino.stackexchange.com/a/31695/62145), Arduino functions can be _overwritten_ by copying complete files into the own project. 
+
+This is used to create a castrated CDC device with a single interface containing 3 endpoints. 
+
+The modifications have been done against Arduino 1.8.10, for changes see comments containing `kai`.
+

test/arduino_leonardo_bridge_castrated_cdc/USBCore.h

@@ -0,0 +1,301 @@
+
+// Copyright (c) 2010, Peter Barrett 
+/*
+** Permission to use, copy, modify, and/or distribute this software for  
+** any purpose with or without fee is hereby granted, provided that the  
+** above copyright notice and this permission notice appear in all copies.  
+**  
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
+** SOFTWARE.  
+*/
+
+#ifndef __USBCORE_H__
+#define __USBCORE_H__
+
+#include "USBAPI.h"
+
+//	Standard requests
+#define GET_STATUS			0
+#define CLEAR_FEATURE		1
+#define SET_FEATURE			3
+#define SET_ADDRESS			5
+#define GET_DESCRIPTOR		6
+#define SET_DESCRIPTOR		7
+#define GET_CONFIGURATION	8
+#define SET_CONFIGURATION	9
+#define GET_INTERFACE		10
+#define SET_INTERFACE		11
+
+
+// bmRequestType
+#define REQUEST_HOSTTODEVICE	0x00
+#define REQUEST_DEVICETOHOST	0x80
+#define REQUEST_DIRECTION		0x80
+
+#define REQUEST_STANDARD		0x00
+#define REQUEST_CLASS			0x20
+#define REQUEST_VENDOR			0x40
+#define REQUEST_TYPE			0x60
+
+#define REQUEST_DEVICE			0x00
+#define REQUEST_INTERFACE		0x01
+#define REQUEST_ENDPOINT		0x02
+#define REQUEST_OTHER			0x03
+#define REQUEST_RECIPIENT		0x03
+
+#define REQUEST_DEVICETOHOST_CLASS_INTERFACE    (REQUEST_DEVICETOHOST | REQUEST_CLASS | REQUEST_INTERFACE)
+#define REQUEST_HOSTTODEVICE_CLASS_INTERFACE    (REQUEST_HOSTTODEVICE | REQUEST_CLASS | REQUEST_INTERFACE)
+#define REQUEST_DEVICETOHOST_STANDARD_INTERFACE (REQUEST_DEVICETOHOST | REQUEST_STANDARD | REQUEST_INTERFACE)
+
+//	Class requests
+
+#define CDC_SET_LINE_CODING			0x20
+#define CDC_GET_LINE_CODING			0x21
+#define CDC_SET_CONTROL_LINE_STATE	0x22
+#define CDC_SEND_BREAK				0x23
+
+#define MSC_RESET					0xFF
+#define MSC_GET_MAX_LUN				0xFE
+
+//	Descriptors
+
+#define USB_DEVICE_DESC_SIZE 18
+#define USB_CONFIGUARTION_DESC_SIZE 9
+#define USB_INTERFACE_DESC_SIZE 9
+#define USB_ENDPOINT_DESC_SIZE 7
+
+#define USB_DEVICE_DESCRIPTOR_TYPE             1
+#define USB_CONFIGURATION_DESCRIPTOR_TYPE      2
+#define USB_STRING_DESCRIPTOR_TYPE             3
+#define USB_INTERFACE_DESCRIPTOR_TYPE          4
+#define USB_ENDPOINT_DESCRIPTOR_TYPE           5
+
+// usb_20.pdf Table 9.6 Standard Feature Selectors
+#define DEVICE_REMOTE_WAKEUP                   1
+#define ENDPOINT_HALT                          2
+#define TEST_MODE                              3
+
+// usb_20.pdf Figure 9-4. Information Returned by a GetStatus() Request to a Device
+#define FEATURE_SELFPOWERED_ENABLED     (1 << 0)
+#define FEATURE_REMOTE_WAKEUP_ENABLED   (1 << 1)
+
+#define USB_DEVICE_CLASS_COMMUNICATIONS        0x02
+#define USB_DEVICE_CLASS_HUMAN_INTERFACE       0x03
+#define USB_DEVICE_CLASS_STORAGE               0x08
+#define USB_DEVICE_CLASS_VENDOR_SPECIFIC       0xFF
+
+#define USB_CONFIG_POWERED_MASK                0x40
+#define USB_CONFIG_BUS_POWERED                 0x80
+#define USB_CONFIG_SELF_POWERED                0xC0
+#define USB_CONFIG_REMOTE_WAKEUP               0x20
+
+// bMaxPower in Configuration Descriptor
+#define USB_CONFIG_POWER_MA(mA)                ((mA)/2)
+
+// bEndpointAddress in Endpoint Descriptor
+#define USB_ENDPOINT_DIRECTION_MASK            0x80
+#define USB_ENDPOINT_OUT(addr)                 (lowByte((addr) | 0x00))
+#define USB_ENDPOINT_IN(addr)                  (lowByte((addr) | 0x80))
+
+#define USB_ENDPOINT_TYPE_MASK                 0x03
+#define USB_ENDPOINT_TYPE_CONTROL              0x00
+#define USB_ENDPOINT_TYPE_ISOCHRONOUS          0x01
+#define USB_ENDPOINT_TYPE_BULK                 0x02
+#define USB_ENDPOINT_TYPE_INTERRUPT            0x03
+
+#define TOBYTES(x) ((x) & 0xFF),(((x) >> 8) & 0xFF)
+
+#define CDC_V1_10                               0x0110
+#define CDC_COMMUNICATION_INTERFACE_CLASS       0x02
+
+#define CDC_CALL_MANAGEMENT                     0x01
+#define CDC_ABSTRACT_CONTROL_MODEL              0x02
+#define CDC_HEADER                              0x00
+#define CDC_ABSTRACT_CONTROL_MANAGEMENT         0x02
+#define CDC_UNION                               0x06
+#define CDC_CS_INTERFACE                        0x24
+#define CDC_CS_ENDPOINT                         0x25
+#define CDC_DATA_INTERFACE_CLASS                0x0A
+
+#define MSC_SUBCLASS_SCSI						0x06 
+#define MSC_PROTOCOL_BULK_ONLY					0x50 
+
+#ifndef USB_VERSION
+#define USB_VERSION 0x200
+#endif
+
+//	Device
+typedef struct {
+	u8 len;				// 18
+	u8 dtype;			// 1 USB_DEVICE_DESCRIPTOR_TYPE
+	u16 usbVersion;		// 0x200 or 0x210
+	u8	deviceClass;
+	u8	deviceSubClass;
+	u8	deviceProtocol;
+	u8	packetSize0;	// Packet 0
+	u16	idVendor;
+	u16	idProduct;
+	u16	deviceVersion;	// 0x100
+	u8	iManufacturer;
+	u8	iProduct;
+	u8	iSerialNumber;
+	u8	bNumConfigurations;
+} DeviceDescriptor;
+
+//	Config
+typedef struct {
+	u8	len;			// 9
+	u8	dtype;			// 2
+	u16 clen;			// total length
+	u8	numInterfaces;
+	u8	config;
+	u8	iconfig;
+	u8	attributes;
+	u8	maxPower;
+} ConfigDescriptor;
+
+//	String
+
+//	Interface
+typedef struct
+{
+	u8 len;		// 9
+	u8 dtype;	// 4
+	u8 number;
+	u8 alternate;
+	u8 numEndpoints;
+	u8 interfaceClass;
+	u8 interfaceSubClass;
+	u8 protocol;
+	u8 iInterface;
+} InterfaceDescriptor;
+
+//	Endpoint
+typedef struct
+{
+	u8 len;		// 7
+	u8 dtype;	// 5
+	u8 addr;
+	u8 attr;
+	u16 packetSize;
+	u8 interval;
+} EndpointDescriptor;
+
+// Interface Association Descriptor
+// Used to bind 2 interfaces together in CDC compostite device
+typedef struct
+{
+	u8 len;				// 8
+	u8 dtype;			// 11
+	u8 firstInterface;
+	u8 interfaceCount;
+	u8 functionClass;
+	u8 funtionSubClass;
+	u8 functionProtocol;
+	u8 iInterface;
+} IADDescriptor;
+
+//	CDC CS interface descriptor
+typedef struct
+{
+	u8 len;		// 5
+	u8 dtype;	// 0x24
+	u8 subtype;
+	u8 d0;
+	u8 d1;
+} CDCCSInterfaceDescriptor;
+
+typedef struct
+{
+	u8 len;		// 4
+	u8 dtype;	// 0x24
+	u8 subtype;
+	u8 d0;
+} CDCCSInterfaceDescriptor4;
+
+typedef struct 
+{
+    u8	len;
+    u8 	dtype;		// 0x24
+    u8 	subtype;	// 1
+    u8 	bmCapabilities;
+    u8 	bDataInterface;
+} CMFunctionalDescriptor;
+	
+typedef struct 
+{
+    u8	len;
+    u8 	dtype;		// 0x24
+    u8 	subtype;	// 1
+    u8 	bmCapabilities;
+} ACMFunctionalDescriptor;
+
+typedef struct 
+{
+	//	IAD
+	IADDescriptor				iad;	// Only needed on compound device
+
+	//	Control
+	InterfaceDescriptor			cif;	// 
+	CDCCSInterfaceDescriptor	header;
+	CMFunctionalDescriptor		callManagement;			// Call Management
+	ACMFunctionalDescriptor		controlManagement;		// ACM
+	CDCCSInterfaceDescriptor	functionalDescriptor;	// CDC_UNION
+	EndpointDescriptor			cifin;
+
+	//	Data
+	//InterfaceDescriptor			dif; // kai:removed
+	EndpointDescriptor			in;
+	EndpointDescriptor			out;
+} CDCDescriptor;
+
+typedef struct 
+{
+	InterfaceDescriptor			msc;
+	EndpointDescriptor			in;
+	EndpointDescriptor			out;
+} MSCDescriptor;
+
+
+#define D_DEVICE(_class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs) \
+	{ 18, 1, USB_VERSION, _class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs }
+
+#define D_CONFIG(_totalLength,_interfaces) \
+	{ 9, 2, _totalLength,_interfaces, 1, 0, USB_CONFIG_BUS_POWERED | USB_CONFIG_REMOTE_WAKEUP, USB_CONFIG_POWER_MA(500) }
+
+#define D_INTERFACE(_n,_numEndpoints,_class,_subClass,_protocol) \
+	{ 9, 4, _n, 0, _numEndpoints, _class,_subClass, _protocol, 0 }
+
+#define D_ENDPOINT(_addr,_attr,_packetSize, _interval) \
+	{ 7, 5, _addr,_attr,_packetSize, _interval }
+
+#define D_IAD(_firstInterface, _count, _class, _subClass, _protocol) \
+	{ 8, 11, _firstInterface, _count, _class, _subClass, _protocol, 0 }
+
+#define D_CDCCS(_subtype,_d0,_d1)	{ 5, 0x24, _subtype, _d0, _d1 }
+#define D_CDCCS4(_subtype,_d0)		{ 4, 0x24, _subtype, _d0 }
+
+// Bootloader related fields
+// Old Caterina bootloader places the MAGIC key into unsafe RAM locations (it can be rewritten
+// by the running sketch before to actual reboot).
+// Newer bootloaders, recognizable by the LUFA "signature" at the end of the flash, can handle both
+// the usafe and the safe location.
+#ifndef MAGIC_KEY
+#define MAGIC_KEY 0x7777
+#endif
+
+#ifndef MAGIC_KEY_POS
+#define MAGIC_KEY_POS 0x0800
+#endif
+
+#ifndef NEW_LUFA_SIGNATURE
+#define NEW_LUFA_SIGNATURE 0xDCFB
+#endif
+
+#endif

test/arduino_leonardo_bridge_castrated_cdc/arduino_leonardo_bridge_castrated_cdc.ino

@@ -0,0 +1,64 @@
+/*
+  bridge USB-serial to hardware-serial
+
+  for Arduinos based on ATmega32u4 (Leonardo and compatible Pro Micro, Micro)
+  hardware serial is configured with baud-rate, databits, stopbits, parity as send over USB
+
+  see https://github.com/arduino/Arduino/tree/master/hardware/arduino/avr/cores/arduino 
+  -> CDC.cpp|HardwareSerial.cpp for serial implementation details
+
+  this sketch is mainly for demonstration / test of CDC communication
+  performance as real usb-serial bridge would be inacceptable as each byte is send in separate USB packet
+*/
+
+uint32_t baud = 9600;
+uint8_t databits = 8;
+uint8_t stopbits = 1;
+uint8_t parity = 0;
+
+void setup() {
+  Serial.begin(baud); // USB
+  Serial1.begin(baud, SERIAL_8N1);
+}
+
+void loop() {
+  // show USB connected state
+  if (Serial) TXLED1;
+  else        TXLED0;
+
+  // configure hardware serial
+  if (Serial.baud() != baud ||
+      Serial.numbits() != databits ||
+      Serial.stopbits() != stopbits ||
+      Serial.paritytype() != parity) {
+    baud = Serial.baud();
+    databits = Serial.numbits();
+    stopbits = Serial.stopbits();
+    parity = Serial.paritytype();
+    uint8_t config = 0; // ucsrc register
+    switch (databits) {
+      case 5: break;
+      case 6: config |= 2; break;
+      case 7: config |= 4; break;
+      case 8: config |= 6; break;
+      default: config |= 6;
+    }
+    switch (stopbits) {
+      case 2: config |= 8;
+        // 1.5 stopbits not supported
+    }
+    switch (parity) {
+      case 1: config |= 0x30; break; // odd
+      case 2: config |= 0x20; break; // even
+        // mark, space not supported
+    }
+    Serial1.end();
+    Serial1.begin(baud, config);
+  }
+
+  // bridge
+  if (Serial.available() > 0)
+    Serial1.write(Serial.read());
+  if (Serial1.available() > 0)
+    Serial.write(Serial1.read());
+}

test/arduino_leonardo_bridge_multi_cdc/CDC.cpp

@@ -0,0 +1,320 @@
+
+
+/* Copyright (c) 2011, Peter Barrett  
+**  
+** Permission to use, copy, modify, and/or distribute this software for  
+** any purpose with or without fee is hereby granted, provided that the  
+** above copyright notice and this permission notice appear in all copies.  
+** 
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
+** SOFTWARE.  
+*/
+
+#include "USBCore.h" // kai:added
+#include "USBAPI.h"
+#include "USBDesc.h" // kai:added
+#include <avr/wdt.h>
+#include <util/atomic.h>
+
+#if defined(USBCON)
+
+typedef struct
+{
+	u32	dwDTERate;
+	u8	bCharFormat;
+	u8 	bParityType;
+	u8 	bDataBits;
+	u8	lineState;
+} LineInfo;
+
+static volatile LineInfo _usbLineInfo = { 57600, 0x00, 0x00, 0x00, 0x00 };
+static volatile int32_t breakValue = -1;
+
+static u8 wdtcsr_save;
+
+#define WEAK __attribute__ ((weak))
+
+extern const CDCDescriptor _cdcInterface PROGMEM;
+const CDCDescriptor _cdcInterface =
+{
+	D_IAD(0,2,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,1),
+
+	//	CDC communication interface
+	D_INTERFACE(CDC_ACM_INTERFACE1,1,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,0),
+	D_CDCCS(CDC_HEADER,0x10,0x01),								// Header (1.10 bcd)
+	D_CDCCS(CDC_CALL_MANAGEMENT,1,1),							// Device handles call management (not)
+	D_CDCCS4(CDC_ABSTRACT_CONTROL_MANAGEMENT,6),				// SET_LINE_CODING, GET_LINE_CODING, SET_CONTROL_LINE_STATE supported
+	D_CDCCS(CDC_UNION,CDC_ACM_INTERFACE1,CDC_DATA_INTERFACE1),	// Communication interface is master, data interface is slave 0
+	D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_ACM1),USB_ENDPOINT_TYPE_INTERRUPT,0x10,0x40),
+
+	//	CDC data interface
+	D_INTERFACE(CDC_DATA_INTERFACE1,2,CDC_DATA_INTERFACE_CLASS,0,0),
+	D_ENDPOINT(USB_ENDPOINT_OUT(CDC_ENDPOINT_OUT1),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0),
+	D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_IN1 ),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0)
+	
+	, // kai: added
+  D_IAD(2,2,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,1),
+
+  //  CDC communication interface
+  D_INTERFACE(CDC_ACM_INTERFACE2,1,CDC_COMMUNICATION_INTERFACE_CLASS,CDC_ABSTRACT_CONTROL_MODEL,0),
+  D_CDCCS(CDC_HEADER,0x10,0x01),                // Header (1.10 bcd)
+  D_CDCCS(CDC_CALL_MANAGEMENT,1,1),             // Device handles call management (not)
+  D_CDCCS4(CDC_ABSTRACT_CONTROL_MANAGEMENT,6),        // SET_LINE_CODING, GET_LINE_CODING, SET_CONTROL_LINE_STATE supported
+  D_CDCCS(CDC_UNION,CDC_ACM_INTERFACE2,CDC_DATA_INTERFACE2),  // Communication interface is master, data interface is slave 0
+  D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_ACM2),USB_ENDPOINT_TYPE_INTERRUPT,0x10,0x40),
+  
+  //  CDC data interface
+  D_INTERFACE(CDC_DATA_INTERFACE2,2,CDC_DATA_INTERFACE_CLASS,0,0),
+  D_ENDPOINT(USB_ENDPOINT_OUT(CDC_ENDPOINT_OUT2),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0),
+  D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_IN2),USB_ENDPOINT_TYPE_BULK,USB_EP_SIZE,0)
+};
+
+bool isLUFAbootloader()
+{
+	return pgm_read_word(FLASHEND - 1) == NEW_LUFA_SIGNATURE;
+}
+
+int CDC_GetInterface(u8* interfaceNum)
+{
+	interfaceNum[0] += 4;	// kai
+	return USB_SendControl(TRANSFER_PGM,&_cdcInterface,sizeof(_cdcInterface));
+}
+
+bool CDC_Setup(USBSetup& setup)
+{
+	u8 r = setup.bRequest;
+	u8 requestType = setup.bmRequestType;
+
+	if (REQUEST_DEVICETOHOST_CLASS_INTERFACE == requestType)
+	{
+		if (CDC_GET_LINE_CODING == r)
+		{
+			USB_SendControl(0,(void*)&_usbLineInfo,7);
+			return true;
+		}
+	}
+
+	if (REQUEST_HOSTTODEVICE_CLASS_INTERFACE == requestType)
+	{
+		if (CDC_SEND_BREAK == r)
+		{
+			breakValue = ((uint16_t)setup.wValueH << 8) | setup.wValueL;
+		}
+
+		if (CDC_SET_LINE_CODING == r)
+		{
+			USB_RecvControl((void*)&_usbLineInfo,7);
+		}
+
+		if (CDC_SET_CONTROL_LINE_STATE == r)
+		{
+			_usbLineInfo.lineState = setup.wValueL;
+
+			// auto-reset into the bootloader is triggered when the port, already 
+			// open at 1200 bps, is closed.  this is the signal to start the watchdog
+			// with a relatively long period so it can finish housekeeping tasks
+			// like servicing endpoints before the sketch ends
+
+			uint16_t magic_key_pos = MAGIC_KEY_POS;
+
+// If we don't use the new RAMEND directly, check manually if we have a newer bootloader.
+// This is used to keep compatible with the old leonardo bootloaders.
+// You are still able to set the magic key position manually to RAMEND-1 to save a few bytes for this check.
+#if MAGIC_KEY_POS != (RAMEND-1)
+			// For future boards save the key in the inproblematic RAMEND
+			// Which is reserved for the main() return value (which will never return)
+			if (isLUFAbootloader()) {
+				// horray, we got a new bootloader!
+				magic_key_pos = (RAMEND-1);
+			}
+#endif
+
+			// We check DTR state to determine if host port is open (bit 0 of lineState).
+			if (1200 == _usbLineInfo.dwDTERate && (_usbLineInfo.lineState & 0x01) == 0)
+			{
+#if MAGIC_KEY_POS != (RAMEND-1)
+				// Backup ram value if its not a newer bootloader and it hasn't already been saved.
+				// This should avoid memory corruption at least a bit, not fully
+				if (magic_key_pos != (RAMEND-1) && *(uint16_t *)magic_key_pos != MAGIC_KEY) {
+					*(uint16_t *)(RAMEND-1) = *(uint16_t *)magic_key_pos;
+				}
+#endif
+				// Store boot key
+				*(uint16_t *)magic_key_pos = MAGIC_KEY;
+				// Save the watchdog state in case the reset is aborted.
+				wdtcsr_save = WDTCSR;
+				wdt_enable(WDTO_120MS);
+			}
+			else if (*(uint16_t *)magic_key_pos == MAGIC_KEY)
+			{
+				// Most OSs do some intermediate steps when configuring ports and DTR can
+				// twiggle more than once before stabilizing.
+				// To avoid spurious resets we set the watchdog to 120ms and eventually
+				// cancel if DTR goes back high.
+				// Cancellation is only done if an auto-reset was started, which is
+				// indicated by the magic key having been set.
+
+				wdt_reset();
+				// Restore the watchdog state in case the sketch was using it.
+				WDTCSR |= (1<<WDCE) | (1<<WDE);
+				WDTCSR = wdtcsr_save;
+#if MAGIC_KEY_POS != (RAMEND-1)
+				// Restore backed up (old bootloader) magic key data
+				if (magic_key_pos != (RAMEND-1)) {
+					*(uint16_t *)magic_key_pos = *(uint16_t *)(RAMEND-1);
+				} else
+#endif
+				{
+				// Clean up RAMEND key
+					*(uint16_t *)magic_key_pos = 0x0000;
+				}
+			}
+		}
+		return true;
+	}
+	return false;
+}
+
+
+void Serial_::begin(unsigned long /* baud_count */)
+{
+	peek_buffer = -1;
+}
+
+void Serial_::begin(unsigned long /* baud_count */, byte /* config */)
+{
+	peek_buffer = -1;
+}
+
+void Serial_::end(void)
+{
+}
+
+int Serial_::available(void)
+{
+	if (peek_buffer >= 0) {
+		return 1 + USB_Available(CDC_RX);
+	}
+	return USB_Available(CDC_RX);
+}
+
+int Serial_::peek(void)
+{
+	if (peek_buffer < 0)
+		peek_buffer = USB_Recv(CDC_RX);
+	return peek_buffer;
+}
+
+int Serial_::read(void)
+{
+	if (peek_buffer >= 0) {
+		int c = peek_buffer;
+		peek_buffer = -1;
+		return c;
+	}
+	return USB_Recv(CDC_RX);
+}
+
+int Serial_::availableForWrite(void)
+{
+	return USB_SendSpace(CDC_TX);
+}
+
+void Serial_::flush(void)
+{
+	USB_Flush(CDC_TX);
+}
+
+size_t Serial_::write(uint8_t c)
+{
+	return write(&c, 1);
+}
+
+size_t Serial_::write(const uint8_t *buffer, size_t size)
+{
+	/* only try to send bytes if the high-level CDC connection itself 
+	 is open (not just the pipe) - the OS should set lineState when the port
+	 is opened and clear lineState when the port is closed.
+	 bytes sent before the user opens the connection or after
+	 the connection is closed are lost - just like with a UART. */
+	
+	// TODO - ZE - check behavior on different OSes and test what happens if an
+	// open connection isn't broken cleanly (cable is yanked out, host dies
+	// or locks up, or host virtual serial port hangs)
+	if (_usbLineInfo.lineState > 0)	{
+		int r = USB_Send(CDC_TX,buffer,size);
+		if (r > 0) {
+			return r;
+		} else {
+			setWriteError();
+			return 0;
+		}
+	}
+	setWriteError();
+	return 0;
+}
+
+// This operator is a convenient way for a sketch to check whether the
+// port has actually been configured and opened by the host (as opposed
+// to just being connected to the host).  It can be used, for example, in 
+// setup() before printing to ensure that an application on the host is
+// actually ready to receive and display the data.
+// We add a short delay before returning to fix a bug observed by Federico
+// where the port is configured (lineState != 0) but not quite opened.
+Serial_::operator bool() {
+	bool result = false;
+	if (_usbLineInfo.lineState > 0) 
+		result = true;
+	delay(10);
+	return result;
+}
+
+unsigned long Serial_::baud() {
+	// Disable interrupts while reading a multi-byte value
+	uint32_t baudrate;
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		baudrate =  _usbLineInfo.dwDTERate;
+	}
+	return baudrate;
+}
+
+uint8_t Serial_::stopbits() {
+	return _usbLineInfo.bCharFormat;
+}
+
+uint8_t Serial_::paritytype() {
+	return _usbLineInfo.bParityType;
+}
+
+uint8_t Serial_::numbits() {
+	return _usbLineInfo.bDataBits;
+}
+
+bool Serial_::dtr() {
+	return _usbLineInfo.lineState & 0x1;
+}
+
+bool Serial_::rts() {
+	return _usbLineInfo.lineState & 0x2;
+}
+
+int32_t Serial_::readBreak() {
+	int32_t ret;
+	// Disable IRQs while reading and clearing breakValue to make
+	// sure we don't overwrite a value just set by the ISR.
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		ret = breakValue;
+		breakValue = -1;
+	}
+	return ret;
+}
+
+Serial_ Serial;
+
+#endif /* if defined(USBCON) */

test/arduino_leonardo_bridge_multi_cdc/README.md

@@ -0,0 +1,8 @@
+## multiple CDC interface test
+
+As mentioned [here](https://arduino.stackexchange.com/a/31695/62145),  Arduino functions can be _overwritten_ by copying complete files into the own project. 
+
+This is used to create a device with 2 CDC interfaces. For simplicity only one of both is functional (configurable in USBDesc.h)
+
+The modifications have been done against Arduino 1.8.10, for changes see comments containing `kai`.
+

test/arduino_leonardo_bridge_multi_cdc/USBCore.cpp

@@ -0,0 +1,870 @@
+
+
+/* Copyright (c) 2010, Peter Barrett
+** Sleep/Wakeup support added by Michael Dreher
+**  
+** Permission to use, copy, modify, and/or distribute this software for  
+** any purpose with or without fee is hereby granted, provided that the  
+** above copyright notice and this permission notice appear in all copies.  
+** 
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
+** SOFTWARE.  
+*/
+
+#include "USBAPI.h"
+#include "USBDesc.h" // kai:added
+#include "PluggableUSB.h"
+#include <stdlib.h>
+
+#if defined(USBCON)
+
+/** Pulse generation counters to keep track of the number of milliseconds remaining for each pulse type */
+#define TX_RX_LED_PULSE_MS 100
+volatile u8 TxLEDPulse; /**< Milliseconds remaining for data Tx LED pulse */
+volatile u8 RxLEDPulse; /**< Milliseconds remaining for data Rx LED pulse */
+
+//==================================================================
+//==================================================================
+
+extern const u16 STRING_LANGUAGE[] PROGMEM;
+extern const u8 STRING_PRODUCT[] PROGMEM;
+extern const u8 STRING_MANUFACTURER[] PROGMEM;
+extern const DeviceDescriptor USB_DeviceDescriptorIAD PROGMEM;
+
+const u16 STRING_LANGUAGE[2] = {
+	(3<<8) | (2+2),
+	0x0409	// English
+};
+
+#ifndef USB_PRODUCT
+// If no product is provided, use USB IO Board
+#define USB_PRODUCT     "USB IO Board"
+#endif
+
+const u8 STRING_PRODUCT[] PROGMEM = USB_PRODUCT;
+
+#if USB_VID == 0x2341
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "Arduino LLC"
+#elif USB_VID == 0x1b4f
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "SparkFun"
+#elif !defined(USB_MANUFACTURER)
+// Fall through to unknown if no manufacturer name was provided in a macro
+#  define USB_MANUFACTURER "Unknown"
+#endif
+
+const u8 STRING_MANUFACTURER[] PROGMEM = USB_MANUFACTURER;
+
+
+#define DEVICE_CLASS 0x02
+
+//	DEVICE DESCRIPTOR
+const DeviceDescriptor USB_DeviceDescriptorIAD =
+	D_DEVICE(0xEF,0x02,0x01,64,USB_VID,USB_PID,0x100,IMANUFACTURER,IPRODUCT,ISERIAL,1);
+
+//==================================================================
+//==================================================================
+
+volatile u8 _usbConfiguration = 0;
+volatile u8 _usbCurrentStatus = 0; // meaning of bits see usb_20.pdf, Figure 9-4. Information Returned by a GetStatus() Request to a Device
+volatile u8 _usbSuspendState = 0; // copy of UDINT to check SUSPI and WAKEUPI bits
+
+static inline void WaitIN(void)
+{
+	while (!(UEINTX & (1<<TXINI)))
+		;
+}
+
+static inline void ClearIN(void)
+{
+	UEINTX = ~(1<<TXINI);
+}
+
+static inline void WaitOUT(void)
+{
+	while (!(UEINTX & (1<<RXOUTI)))
+		;
+}
+
+static inline u8 WaitForINOrOUT()
+{
+	while (!(UEINTX & ((1<<TXINI)|(1<<RXOUTI))))
+		;
+	return (UEINTX & (1<<RXOUTI)) == 0;
+}
+
+static inline void ClearOUT(void)
+{
+	UEINTX = ~(1<<RXOUTI);
+}
+
+static inline void Recv(volatile u8* data, u8 count)
+{
+	while (count--)
+		*data++ = UEDATX;
+	
+	RXLED1;					// light the RX LED
+	RxLEDPulse = TX_RX_LED_PULSE_MS;	
+}
+
+static inline u8 Recv8()
+{
+	RXLED1;					// light the RX LED
+	RxLEDPulse = TX_RX_LED_PULSE_MS;
+
+	return UEDATX;	
+}
+
+static inline void Send8(u8 d)
+{
+	UEDATX = d;
+}
+
+static inline void SetEP(u8 ep)
+{
+	UENUM = ep;
+}
+
+static inline u8 FifoByteCount()
+{
+	return UEBCLX;
+}
+
+static inline u8 ReceivedSetupInt()
+{
+	return UEINTX & (1<<RXSTPI);
+}
+
+static inline void ClearSetupInt()
+{
+	UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
+}
+
+static inline void Stall()
+{
+	UECONX = (1<<STALLRQ) | (1<<EPEN);
+}
+
+static inline u8 ReadWriteAllowed()
+{
+	return UEINTX & (1<<RWAL);
+}
+
+static inline u8 Stalled()
+{
+	return UEINTX & (1<<STALLEDI);
+}
+
+static inline u8 FifoFree()
+{
+	return UEINTX & (1<<FIFOCON);
+}
+
+static inline void ReleaseRX()
+{
+	UEINTX = 0x6B;	// FIFOCON=0 NAKINI=1 RWAL=1 NAKOUTI=0 RXSTPI=1 RXOUTI=0 STALLEDI=1 TXINI=1
+}
+
+static inline void ReleaseTX()
+{
+	UEINTX = 0x3A;	// FIFOCON=0 NAKINI=0 RWAL=1 NAKOUTI=1 RXSTPI=1 RXOUTI=0 STALLEDI=1 TXINI=0
+}
+
+static inline u8 FrameNumber()
+{
+	return UDFNUML;
+}
+
+//==================================================================
+//==================================================================
+
+u8 USBGetConfiguration(void)
+{
+	return _usbConfiguration;
+}
+
+#define USB_RECV_TIMEOUT
+class LockEP
+{
+	u8 _sreg;
+public:
+	LockEP(u8 ep) : _sreg(SREG)
+	{
+		cli();
+		SetEP(ep & 7);
+	}
+	~LockEP()
+	{
+		SREG = _sreg;
+	}
+};
+
+//	Number of bytes, assumes a rx endpoint
+u8 USB_Available(u8 ep)
+{
+	LockEP lock(ep);
+	return FifoByteCount();
+}
+
+//	Non Blocking receive
+//	Return number of bytes read
+int USB_Recv(u8 ep, void* d, int len)
+{
+	if (!_usbConfiguration || len < 0)
+		return -1;
+	
+	LockEP lock(ep);
+	u8 n = FifoByteCount();
+	len = min(n,len);
+	n = len;
+	u8* dst = (u8*)d;
+	while (n--)
+		*dst++ = Recv8();
+	if (len && !FifoByteCount())	// release empty buffer
+		ReleaseRX();
+	
+	return len;
+}
+
+//	Recv 1 byte if ready
+int USB_Recv(u8 ep)
+{
+	u8 c;
+	if (USB_Recv(ep,&c,1) != 1)
+		return -1;
+	return c;
+}
+
+//	Space in send EP
+u8 USB_SendSpace(u8 ep)
+{
+	LockEP lock(ep);
+	if (!ReadWriteAllowed())
+		return 0;
+	return USB_EP_SIZE - FifoByteCount();
+}
+
+//	Blocking Send of data to an endpoint
+int USB_Send(u8 ep, const void* d, int len)
+{
+	if (!_usbConfiguration)
+		return -1;
+
+	if (_usbSuspendState & (1<<SUSPI)) {
+		//send a remote wakeup
+		UDCON |= (1 << RMWKUP);
+	}
+
+	int r = len;
+	const u8* data = (const u8*)d;
+	u8 timeout = 250;		// 250ms timeout on send? TODO
+	bool sendZlp = false;
+
+	while (len || sendZlp)
+	{
+		u8 n = USB_SendSpace(ep);
+		if (n == 0)
+		{
+			if (!(--timeout))
+				return -1;
+			delay(1);
+			continue;
+		}
+
+		if (n > len) {
+			n = len;
+		}
+
+		{
+			LockEP lock(ep);
+			// Frame may have been released by the SOF interrupt handler
+			if (!ReadWriteAllowed())
+				continue;
+
+			len -= n;
+			if (ep & TRANSFER_ZERO)
+			{
+				while (n--)
+					Send8(0);
+			}
+			else if (ep & TRANSFER_PGM)
+			{
+				while (n--)
+					Send8(pgm_read_byte(data++));
+			}
+			else
+			{
+				while (n--)
+					Send8(*data++);
+			}
+
+			if (sendZlp) {
+				ReleaseTX();
+				sendZlp = false;
+			} else if (!ReadWriteAllowed()) { // ...release if buffer is full...
+				ReleaseTX();
+				if (len == 0) sendZlp = true;
+			} else if ((len == 0) && (ep & TRANSFER_RELEASE)) { // ...or if forced with TRANSFER_RELEASE
+				// XXX: TRANSFER_RELEASE is never used can be removed?
+				ReleaseTX();
+			}
+		}
+	}
+	TXLED1;					// light the TX LED
+	TxLEDPulse = TX_RX_LED_PULSE_MS;
+	return r;
+}
+
+u8 _initEndpoints[USB_ENDPOINTS] =
+{
+	0,                      // Control Endpoint
+	
+  EP_TYPE_INTERRUPT_IN,   // CDC_ENDPOINT_ACM
+  EP_TYPE_BULK_OUT,       // CDC_ENDPOINT_OUT
+  EP_TYPE_BULK_IN,        // CDC_ENDPOINT_IN
+
+  // kai:added
+  EP_TYPE_INTERRUPT_IN,   // CDC_ENDPOINT_ACM
+  EP_TYPE_BULK_OUT,       // CDC_ENDPOINT_OUT
+  EP_TYPE_BULK_IN,        // CDC_ENDPOINT_IN
+
+	// Following endpoints are automatically initialized to 0
+};
+
+#define EP_SINGLE_64 0x32	// EP0
+#define EP_DOUBLE_64 0x36	// Other endpoints
+#define EP_SINGLE_16 0x12
+
+static
+void InitEP(u8 index, u8 type, u8 size)
+{
+	UENUM = index;
+	UECONX = (1<<EPEN);
+	UECFG0X = type;
+	UECFG1X = size;
+}
+
+static
+void InitEndpoints()
+{
+	for (u8 i = 1; i < sizeof(_initEndpoints) && _initEndpoints[i] != 0; i++)
+	{
+		UENUM = i;
+		UECONX = (1<<EPEN);
+		UECFG0X = _initEndpoints[i];
+#if USB_EP_SIZE == 16
+		UECFG1X = EP_SINGLE_16;
+#elif USB_EP_SIZE == 64
+		UECFG1X = EP_DOUBLE_64;
+#else
+#error Unsupported value for USB_EP_SIZE
+#endif
+	}
+	UERST = 0x7E;	// And reset them
+	UERST = 0;
+}
+
+//	Handle CLASS_INTERFACE requests
+static
+bool ClassInterfaceRequest(USBSetup& setup)
+{
+	u8 i = setup.wIndex;
+
+  if (CDC_CLASS_INTERFACE == i) // kai
+    return CDC_Setup(setup);
+
+#ifdef PLUGGABLE_USB_ENABLED
+	return PluggableUSB().setup(setup);
+#endif
+	return false;
+}
+
+static int _cmark;
+static int _cend;
+void InitControl(int end)
+{
+	SetEP(0);
+	_cmark = 0;
+	_cend = end;
+}
+
+static
+bool SendControl(u8 d)
+{
+	if (_cmark < _cend)
+	{
+		if (!WaitForINOrOUT())
+			return false;
+		Send8(d);
+		if (!((_cmark + 1) & 0x3F))
+			ClearIN();	// Fifo is full, release this packet
+	}
+	_cmark++;
+	return true;
+}
+
+//	Clipped by _cmark/_cend
+int USB_SendControl(u8 flags, const void* d, int len)
+{
+	int sent = len;
+	const u8* data = (const u8*)d;
+	bool pgm = flags & TRANSFER_PGM;
+	while (len--)
+	{
+		u8 c = pgm ? pgm_read_byte(data++) : *data++;
+		if (!SendControl(c))
+			return -1;
+	}
+	return sent;
+}
+
+// Send a USB descriptor string. The string is stored in PROGMEM as a
+// plain ASCII string but is sent out as UTF-16 with the correct 2-byte
+// prefix
+static bool USB_SendStringDescriptor(const u8*string_P, u8 string_len, uint8_t flags) {
+        SendControl(2 + string_len * 2);
+        SendControl(3);
+        bool pgm = flags & TRANSFER_PGM;
+        for(u8 i = 0; i < string_len; i++) {
+                bool r = SendControl(pgm ? pgm_read_byte(&string_P[i]) : string_P[i]);
+                r &= SendControl(0); // high byte
+                if(!r) {
+                        return false;
+                }
+        }
+        return true;
+}
+
+//	Does not timeout or cross fifo boundaries
+int USB_RecvControl(void* d, int len)
+{
+	auto length = len;
+	while(length)
+	{
+		// Dont receive more than the USB Control EP has to offer
+		// Use fixed 64 because control EP always have 64 bytes even on 16u2.
+		auto recvLength = length;
+		if(recvLength > 64){
+			recvLength = 64;
+		}
+
+		// Write data to fit to the end (not the beginning) of the array
+		WaitOUT();
+		Recv((u8*)d + len - length, recvLength);
+		ClearOUT();
+		length -= recvLength;
+	}
+	return len;
+}
+
+static u8 SendInterfaces()
+{
+	u8 interfaces = 0;
+
+	CDC_GetInterface(&interfaces);
+
+#ifdef PLUGGABLE_USB_ENABLED
+	PluggableUSB().getInterface(&interfaces);
+#endif
+
+	return interfaces;
+}
+
+//	Construct a dynamic configuration descriptor
+//	This really needs dynamic endpoint allocation etc
+//	TODO
+static
+bool SendConfiguration(int maxlen)
+{
+	//	Count and measure interfaces
+	InitControl(0);
+	u8 interfaces = SendInterfaces();
+	ConfigDescriptor config = D_CONFIG(_cmark + sizeof(ConfigDescriptor),interfaces);
+
+	//	Now send them
+	InitControl(maxlen);
+	USB_SendControl(0,&config,sizeof(ConfigDescriptor));
+	SendInterfaces();
+	return true;
+}
+
+static
+bool SendDescriptor(USBSetup& setup)
+{
+	int ret;
+	u8 t = setup.wValueH;
+	if (USB_CONFIGURATION_DESCRIPTOR_TYPE == t)
+		return SendConfiguration(setup.wLength);
+
+	InitControl(setup.wLength);
+#ifdef PLUGGABLE_USB_ENABLED
+	ret = PluggableUSB().getDescriptor(setup);
+	if (ret != 0) {
+		return (ret > 0 ? true : false);
+	}
+#endif
+
+	const u8* desc_addr = 0;
+	if (USB_DEVICE_DESCRIPTOR_TYPE == t)
+	{
+		desc_addr = (const u8*)&USB_DeviceDescriptorIAD;
+	}
+	else if (USB_STRING_DESCRIPTOR_TYPE == t)
+	{
+		if (setup.wValueL == 0) {
+			desc_addr = (const u8*)&STRING_LANGUAGE;
+		}
+		else if (setup.wValueL == IPRODUCT) {
+			return USB_SendStringDescriptor(STRING_PRODUCT, strlen(USB_PRODUCT), TRANSFER_PGM);
+		}
+		else if (setup.wValueL == IMANUFACTURER) {
+			return USB_SendStringDescriptor(STRING_MANUFACTURER, strlen(USB_MANUFACTURER), TRANSFER_PGM);
+		}
+		else if (setup.wValueL == ISERIAL) {
+#ifdef PLUGGABLE_USB_ENABLED
+			char name[ISERIAL_MAX_LEN];
+			PluggableUSB().getShortName(name);
+			return USB_SendStringDescriptor((uint8_t*)name, strlen(name), 0);
+#endif
+		}
+		else
+			return false;
+	}
+
+	if (desc_addr == 0)
+		return false;
+	u8 desc_length = pgm_read_byte(desc_addr);
+
+	USB_SendControl(TRANSFER_PGM,desc_addr,desc_length);
+	return true;
+}
+
+//	Endpoint 0 interrupt
+ISR(USB_COM_vect)
+{
+    SetEP(0);
+	if (!ReceivedSetupInt())
+		return;
+
+	USBSetup setup;
+	Recv((u8*)&setup,8);
+	ClearSetupInt();
+
+	u8 requestType = setup.bmRequestType;
+	if (requestType & REQUEST_DEVICETOHOST)
+		WaitIN();
+	else
+		ClearIN();
+
+    bool ok = true;
+	if (REQUEST_STANDARD == (requestType & REQUEST_TYPE))
+	{
+		//	Standard Requests
+		u8 r = setup.bRequest;
+		u16 wValue = setup.wValueL | (setup.wValueH << 8);
+		if (GET_STATUS == r)
+		{
+			if (requestType == (REQUEST_DEVICETOHOST | REQUEST_STANDARD | REQUEST_DEVICE))
+			{
+				Send8(_usbCurrentStatus);
+				Send8(0);
+			}
+			else
+			{
+				// TODO: handle the HALT state of an endpoint here
+				// see "Figure 9-6. Information Returned by a GetStatus() Request to an Endpoint" in usb_20.pdf for more information
+				Send8(0);
+				Send8(0);
+			}
+		}
+		else if (CLEAR_FEATURE == r)
+		{
+			if((requestType == (REQUEST_HOSTTODEVICE | REQUEST_STANDARD | REQUEST_DEVICE))
+				&& (wValue == DEVICE_REMOTE_WAKEUP))
+			{
+				_usbCurrentStatus &= ~FEATURE_REMOTE_WAKEUP_ENABLED;
+			}
+		}
+		else if (SET_FEATURE == r)
+		{
+			if((requestType == (REQUEST_HOSTTODEVICE | REQUEST_STANDARD | REQUEST_DEVICE))
+				&& (wValue == DEVICE_REMOTE_WAKEUP))
+			{
+				_usbCurrentStatus |= FEATURE_REMOTE_WAKEUP_ENABLED;
+			}
+		}
+		else if (SET_ADDRESS == r)
+		{
+			WaitIN();
+			UDADDR = setup.wValueL | (1<<ADDEN);
+		}
+		else if (GET_DESCRIPTOR == r)
+		{
+			ok = SendDescriptor(setup);
+		}
+		else if (SET_DESCRIPTOR == r)
+		{
+			ok = false;
+		}
+		else if (GET_CONFIGURATION == r)
+		{
+			Send8(1);
+		}
+		else if (SET_CONFIGURATION == r)
+		{
+			if (REQUEST_DEVICE == (requestType & REQUEST_RECIPIENT))
+			{
+				InitEndpoints();
+				_usbConfiguration = setup.wValueL;
+			} else
+				ok = false;
+		}
+		else if (GET_INTERFACE == r)
+		{
+		}
+		else if (SET_INTERFACE == r)
+		{
+		}
+	}
+	else
+	{
+		InitControl(setup.wLength);		//	Max length of transfer
+		ok = ClassInterfaceRequest(setup);
+	}
+
+	if (ok)
+		ClearIN();
+	else
+	{
+		Stall();
+	}
+}
+
+void USB_Flush(u8 ep)
+{
+	SetEP(ep);
+	if (FifoByteCount())
+		ReleaseTX();
+}
+
+static inline void USB_ClockDisable()
+{
+#if defined(OTGPADE)
+	USBCON = (USBCON & ~(1<<OTGPADE)) | (1<<FRZCLK); // freeze clock and disable VBUS Pad
+#else // u2 Series
+	USBCON = (1 << FRZCLK); // freeze clock
+#endif
+	PLLCSR &= ~(1<<PLLE);  // stop PLL
+}
+
+static inline void USB_ClockEnable()
+{
+#if defined(UHWCON)
+	UHWCON |= (1<<UVREGE);			// power internal reg
+#endif
+	USBCON = (1<<USBE) | (1<<FRZCLK);	// clock frozen, usb enabled
+
+// ATmega32U4
+#if defined(PINDIV)
+#if F_CPU == 16000000UL
+	PLLCSR |= (1<<PINDIV);                   // Need 16 MHz xtal
+#elif F_CPU == 8000000UL
+	PLLCSR &= ~(1<<PINDIV);                  // Need  8 MHz xtal
+#else
+#error "Clock rate of F_CPU not supported"
+#endif
+
+#elif defined(__AVR_AT90USB82__) || defined(__AVR_AT90USB162__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega8U2__)
+	// for the u2 Series the datasheet is confusing. On page 40 its called PINDIV and on page 290 its called PLLP0
+#if F_CPU == 16000000UL
+	// Need 16 MHz xtal
+	PLLCSR |= (1 << PLLP0);
+#elif F_CPU == 8000000UL
+	// Need 8 MHz xtal
+	PLLCSR &= ~(1 << PLLP0);
+#endif
+
+// AT90USB646, AT90USB647, AT90USB1286, AT90USB1287
+#elif defined(PLLP2)
+#if F_CPU == 16000000UL
+#if defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
+	// For Atmel AT90USB128x only. Do not use with Atmel AT90USB64x.
+	PLLCSR = (PLLCSR & ~(1<<PLLP1)) | ((1<<PLLP2) | (1<<PLLP0)); // Need 16 MHz xtal
+#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__)
+	// For AT90USB64x only. Do not use with AT90USB128x.
+	PLLCSR = (PLLCSR & ~(1<<PLLP0)) | ((1<<PLLP2) | (1<<PLLP1)); // Need 16 MHz xtal
+#else
+#error "USB Chip not supported, please defined method of USB PLL initialization"
+#endif
+#elif F_CPU == 8000000UL
+	// for Atmel AT90USB128x and AT90USB64x
+	PLLCSR = (PLLCSR & ~(1<<PLLP2)) | ((1<<PLLP1) | (1<<PLLP0)); // Need 8 MHz xtal
+#else
+#error "Clock rate of F_CPU not supported"
+#endif
+#else
+#error "USB Chip not supported, please defined method of USB PLL initialization"
+#endif
+
+	PLLCSR |= (1<<PLLE);
+	while (!(PLLCSR & (1<<PLOCK)))		// wait for lock pll
+	{
+	}
+
+	// Some tests on specific versions of macosx (10.7.3), reported some
+	// strange behaviors when the board is reset using the serial
+	// port touch at 1200 bps. This delay fixes this behavior.
+	delay(1);
+#if defined(OTGPADE)
+	USBCON = (USBCON & ~(1<<FRZCLK)) | (1<<OTGPADE);	// start USB clock, enable VBUS Pad
+#else
+	USBCON &= ~(1 << FRZCLK);	// start USB clock
+#endif
+
+#if defined(RSTCPU)
+#if defined(LSM)
+	UDCON &= ~((1<<RSTCPU) | (1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
+#else // u2 Series
+	UDCON &= ~((1 << RSTCPU) | (1 << RMWKUP) | (1 << DETACH));	// enable attach resistor, set full speed mode
+#endif
+#else
+	// AT90USB64x and AT90USB128x don't have RSTCPU
+	UDCON &= ~((1<<LSM) | (1<<RMWKUP) | (1<<DETACH));	// enable attach resistor, set full speed mode
+#endif
+}
+
+//	General interrupt
+ISR(USB_GEN_vect)
+{
+	u8 udint = UDINT;
+	UDINT &= ~((1<<EORSTI) | (1<<SOFI)); // clear the IRQ flags for the IRQs which are handled here, except WAKEUPI and SUSPI (see below)
+
+	//	End of Reset
+	if (udint & (1<<EORSTI))
+	{
+		InitEP(0,EP_TYPE_CONTROL,EP_SINGLE_64);	// init ep0
+		_usbConfiguration = 0;			// not configured yet
+		UEIENX = 1 << RXSTPE;			// Enable interrupts for ep0
+	}
+
+	//	Start of Frame - happens every millisecond so we use it for TX and RX LED one-shot timing, too
+	if (udint & (1<<SOFI))
+	{
+		USB_Flush(CDC_TX);				// Send a tx frame if found
+		
+		// check whether the one-shot period has elapsed.  if so, turn off the LED
+		if (TxLEDPulse && !(--TxLEDPulse))
+			TXLED0;
+		if (RxLEDPulse && !(--RxLEDPulse))
+			RXLED0;
+	}
+
+	// the WAKEUPI interrupt is triggered as soon as there are non-idle patterns on the data
+	// lines. Thus, the WAKEUPI interrupt can occur even if the controller is not in the "suspend" mode.
+	// Therefore the we enable it only when USB is suspended
+	if (udint & (1<<WAKEUPI))
+	{
+		UDIEN = (UDIEN & ~(1<<WAKEUPE)) | (1<<SUSPE); // Disable interrupts for WAKEUP and enable interrupts for SUSPEND
+
+		//TODO
+		// WAKEUPI shall be cleared by software (USB clock inputs must be enabled before).
+		//USB_ClockEnable();
+		UDINT &= ~(1<<WAKEUPI);
+		_usbSuspendState = (_usbSuspendState & ~(1<<SUSPI)) | (1<<WAKEUPI);
+	}
+	else if (udint & (1<<SUSPI)) // only one of the WAKEUPI / SUSPI bits can be active at time
+	{
+		UDIEN = (UDIEN & ~(1<<SUSPE)) | (1<<WAKEUPE); // Disable interrupts for SUSPEND and enable interrupts for WAKEUP
+
+		//TODO
+		//USB_ClockDisable();
+
+		UDINT &= ~((1<<WAKEUPI) | (1<<SUSPI)); // clear any already pending WAKEUP IRQs and the SUSPI request
+		_usbSuspendState = (_usbSuspendState & ~(1<<WAKEUPI)) | (1<<SUSPI);
+	}
+}
+
+//	VBUS or counting frames
+//	Any frame counting?
+u8 USBConnected()
+{
+	u8 f = UDFNUML;
+	delay(3);
+	return f != UDFNUML;
+}
+
+//=======================================================================
+//=======================================================================
+
+USBDevice_ USBDevice;
+
+USBDevice_::USBDevice_()
+{
+}
+
+void USBDevice_::attach()
+{
+	_usbConfiguration = 0;
+	_usbCurrentStatus = 0;
+	_usbSuspendState = 0;
+	USB_ClockEnable();
+
+	UDINT &= ~((1<<WAKEUPI) | (1<<SUSPI)); // clear already pending WAKEUP / SUSPEND requests
+	UDIEN = (1<<EORSTE) | (1<<SOFE) | (1<<SUSPE);	// Enable interrupts for EOR (End of Reset), SOF (start of frame) and SUSPEND
+	
+	TX_RX_LED_INIT;
+}
+
+void USBDevice_::detach()
+{
+}
+
+//	Check for interrupts
+//	TODO: VBUS detection
+bool USBDevice_::configured()
+{
+	return _usbConfiguration;
+}
+
+void USBDevice_::poll()
+{
+}
+
+bool USBDevice_::wakeupHost()
+{
+	// clear any previous wakeup request which might have been set but could be processed at that time
+	// e.g. because the host was not suspended at that time
+	UDCON &= ~(1 << RMWKUP);
+
+	if(!(UDCON & (1 << RMWKUP))
+	  && (_usbSuspendState & (1<<SUSPI))
+	  && (_usbCurrentStatus & FEATURE_REMOTE_WAKEUP_ENABLED))
+	{
+		// This short version will only work, when the device has not been suspended. Currently the
+		// Arduino core doesn't handle SUSPEND at all, so this is ok.
+		USB_ClockEnable();
+		UDCON |= (1 << RMWKUP); // send the wakeup request
+		return true;
+	}
+
+	return false;
+}
+
+bool USBDevice_::isSuspended()
+{
+	return (_usbSuspendState & (1 << SUSPI));
+}
+
+
+#endif /* if defined(USBCON) */

test/arduino_leonardo_bridge_multi_cdc/USBCore.h

@@ -0,0 +1,317 @@
+
+// Copyright (c) 2010, Peter Barrett 
+/*
+** Permission to use, copy, modify, and/or distribute this software for  
+** any purpose with or without fee is hereby granted, provided that the  
+** above copyright notice and this permission notice appear in all copies.  
+**  
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR  
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES  
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,  
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,  
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS  
+** SOFTWARE.  
+*/
+
+#ifndef __USBCORE_H__
+#define __USBCORE_H__
+
+#include "USBAPI.h"
+
+//	Standard requests
+#define GET_STATUS			0
+#define CLEAR_FEATURE		1
+#define SET_FEATURE			3
+#define SET_ADDRESS			5
+#define GET_DESCRIPTOR		6
+#define SET_DESCRIPTOR		7
+#define GET_CONFIGURATION	8
+#define SET_CONFIGURATION	9
+#define GET_INTERFACE		10
+#define SET_INTERFACE		11
+
+
+// bmRequestType
+#define REQUEST_HOSTTODEVICE	0x00
+#define REQUEST_DEVICETOHOST	0x80
+#define REQUEST_DIRECTION		0x80
+
+#define REQUEST_STANDARD		0x00
+#define REQUEST_CLASS			0x20
+#define REQUEST_VENDOR			0x40
+#define REQUEST_TYPE			0x60
+
+#define REQUEST_DEVICE			0x00
+#define REQUEST_INTERFACE		0x01
+#define REQUEST_ENDPOINT		0x02
+#define REQUEST_OTHER			0x03
+#define REQUEST_RECIPIENT		0x03
+
+#define REQUEST_DEVICETOHOST_CLASS_INTERFACE    (REQUEST_DEVICETOHOST | REQUEST_CLASS | REQUEST_INTERFACE)
+#define REQUEST_HOSTTODEVICE_CLASS_INTERFACE    (REQUEST_HOSTTODEVICE | REQUEST_CLASS | REQUEST_INTERFACE)
+#define REQUEST_DEVICETOHOST_STANDARD_INTERFACE (REQUEST_DEVICETOHOST | REQUEST_STANDARD | REQUEST_INTERFACE)
+
+//	Class requests
+
+#define CDC_SET_LINE_CODING			0x20
+#define CDC_GET_LINE_CODING			0x21
+#define CDC_SET_CONTROL_LINE_STATE	0x22
+#define CDC_SEND_BREAK				0x23
+
+#define MSC_RESET					0xFF
+#define MSC_GET_MAX_LUN				0xFE
+
+//	Descriptors
+
+#define USB_DEVICE_DESC_SIZE 18
+#define USB_CONFIGUARTION_DESC_SIZE 9
+#define USB_INTERFACE_DESC_SIZE 9
+#define USB_ENDPOINT_DESC_SIZE 7
+
+#define USB_DEVICE_DESCRIPTOR_TYPE             1
+#define USB_CONFIGURATION_DESCRIPTOR_TYPE      2
+#define USB_STRING_DESCRIPTOR_TYPE             3
+#define USB_INTERFACE_DESCRIPTOR_TYPE          4
+#define USB_ENDPOINT_DESCRIPTOR_TYPE           5
+
+// usb_20.pdf Table 9.6 Standard Feature Selectors
+#define DEVICE_REMOTE_WAKEUP                   1
+#define ENDPOINT_HALT                          2
+#define TEST_MODE                              3
+
+// usb_20.pdf Figure 9-4. Information Returned by a GetStatus() Request to a Device
+#define FEATURE_SELFPOWERED_ENABLED     (1 << 0)
+#define FEATURE_REMOTE_WAKEUP_ENABLED   (1 << 1)
+
+#define USB_DEVICE_CLASS_COMMUNICATIONS        0x02
+#define USB_DEVICE_CLASS_HUMAN_INTERFACE       0x03
+#define USB_DEVICE_CLASS_STORAGE               0x08
+#define USB_DEVICE_CLASS_VENDOR_SPECIFIC       0xFF
+
+#define USB_CONFIG_POWERED_MASK                0x40
+#define USB_CONFIG_BUS_POWERED                 0x80
+#define USB_CONFIG_SELF_POWERED                0xC0
+#define USB_CONFIG_REMOTE_WAKEUP               0x20
+
+// bMaxPower in Configuration Descriptor
+#define USB_CONFIG_POWER_MA(mA)                ((mA)/2)
+
+// bEndpointAddress in Endpoint Descriptor
+#define USB_ENDPOINT_DIRECTION_MASK            0x80
+#define USB_ENDPOINT_OUT(addr)                 (lowByte((addr) | 0x00))
+#define USB_ENDPOINT_IN(addr)                  (lowByte((addr) | 0x80))
+
+#define USB_ENDPOINT_TYPE_MASK                 0x03
+#define USB_ENDPOINT_TYPE_CONTROL              0x00
+#define USB_ENDPOINT_TYPE_ISOCHRONOUS          0x01
+#define USB_ENDPOINT_TYPE_BULK                 0x02
+#define USB_ENDPOINT_TYPE_INTERRUPT            0x03
+
+#define TOBYTES(x) ((x) & 0xFF),(((x) >> 8) & 0xFF)
+
+#define CDC_V1_10                               0x0110
+#define CDC_COMMUNICATION_INTERFACE_CLASS       0x02
+
+#define CDC_CALL_MANAGEMENT                     0x01
+#define CDC_ABSTRACT_CONTROL_MODEL              0x02
+#define CDC_HEADER                              0x00
+#define CDC_ABSTRACT_CONTROL_MANAGEMENT         0x02
+#define CDC_UNION                               0x06
+#define CDC_CS_INTERFACE                        0x24
+#define CDC_CS_ENDPOINT                         0x25
+#define CDC_DATA_INTERFACE_CLASS                0x0A
+
+#define MSC_SUBCLASS_SCSI						0x06 
+#define MSC_PROTOCOL_BULK_ONLY					0x50 
+
+#ifndef USB_VERSION
+#define USB_VERSION 0x200
+#endif
+
+//	Device
+typedef struct {
+	u8 len;				// 18
+	u8 dtype;			// 1 USB_DEVICE_DESCRIPTOR_TYPE
+	u16 usbVersion;		// 0x200 or 0x210
+	u8	deviceClass;
+	u8	deviceSubClass;
+	u8	deviceProtocol;
+	u8	packetSize0;	// Packet 0
+	u16	idVendor;
+	u16	idProduct;
+	u16	deviceVersion;	// 0x100
+	u8	iManufacturer;
+	u8	iProduct;
+	u8	iSerialNumber;
+	u8	bNumConfigurations;
+} DeviceDescriptor;
+
+//	Config
+typedef struct {
+	u8	len;			// 9
+	u8	dtype;			// 2
+	u16 clen;			// total length
+	u8	numInterfaces;
+	u8	config;
+	u8	iconfig;
+	u8	attributes;
+	u8	maxPower;
+} ConfigDescriptor;
+
+//	String
+
+//	Interface
+typedef struct
+{
+	u8 len;		// 9
+	u8 dtype;	// 4
+	u8 number;
+	u8 alternate;
+	u8 numEndpoints;
+	u8 interfaceClass;
+	u8 interfaceSubClass;
+	u8 protocol;
+	u8 iInterface;
+} InterfaceDescriptor;
+
+//	Endpoint
+typedef struct
+{
+	u8 len;		// 7
+	u8 dtype;	// 5
+	u8 addr;
+	u8 attr;
+	u16 packetSize;
+	u8 interval;
+} EndpointDescriptor;
+
+// Interface Association Descriptor
+// Used to bind 2 interfaces together in CDC compostite device
+typedef struct
+{
+	u8 len;				// 8
+	u8 dtype;			// 11
+	u8 firstInterface;
+	u8 interfaceCount;
+	u8 functionClass;
+	u8 funtionSubClass;
+	u8 functionProtocol;
+	u8 iInterface;
+} IADDescriptor;
+
+//	CDC CS interface descriptor
+typedef struct
+{
+	u8 len;		// 5
+	u8 dtype;	// 0x24
+	u8 subtype;
+	u8 d0;
+	u8 d1;
+} CDCCSInterfaceDescriptor;
+
+typedef struct
+{
+	u8 len;		// 4
+	u8 dtype;	// 0x24
+	u8 subtype;
+	u8 d0;
+} CDCCSInterfaceDescriptor4;
+
+typedef struct 
+{
+    u8	len;
+    u8 	dtype;		// 0x24
+    u8 	subtype;	// 1
+    u8 	bmCapabilities;
+    u8 	bDataInterface;
+} CMFunctionalDescriptor;
+	
+typedef struct 
+{
+    u8	len;
+    u8 	dtype;		// 0x24
+    u8 	subtype;	// 1
+    u8 	bmCapabilities;
+} ACMFunctionalDescriptor;
+
+typedef struct 
+{
+	//	IAD
+	IADDescriptor				iad;	// Only needed on compound device
+
+	//	Control
+	InterfaceDescriptor			cif;	// 
+	CDCCSInterfaceDescriptor	header;
+	CMFunctionalDescriptor		callManagement;			// Call Management
+	ACMFunctionalDescriptor		controlManagement;		// ACM
+	CDCCSInterfaceDescriptor	functionalDescriptor;	// CDC_UNION
+	EndpointDescriptor			cifin;
+
+	//	Data
+	InterfaceDescriptor			dif;
+	EndpointDescriptor			in;
+	EndpointDescriptor			out;
+
+  // kai:added
+  IADDescriptor       iad2;  // Only needed on compound device
+
+  //  Control
+  InterfaceDescriptor     cif2;  // 
+  CDCCSInterfaceDescriptor  header2;
+  CMFunctionalDescriptor    callManagement2;     // Call Management
+  ACMFunctionalDescriptor   controlManagement2;    // ACM
+  CDCCSInterfaceDescriptor  functionalDescriptor2; // CDC_UNION
+  EndpointDescriptor      cifin2;
+
+  //  Data
+  InterfaceDescriptor     dif2;
+  EndpointDescriptor      in2;
+  EndpointDescriptor      out2;
+} CDCDescriptor;
+
+typedef struct 
+{
+	InterfaceDescriptor			msc;
+	EndpointDescriptor			in;
+	EndpointDescriptor			out;
+} MSCDescriptor;
+
+
+#define D_DEVICE(_class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs) \
+	{ 18, 1, USB_VERSION, _class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs }
+
+#define D_CONFIG(_totalLength,_interfaces) \
+	{ 9, 2, _totalLength,_interfaces, 1, 0, USB_CONFIG_BUS_POWERED | USB_CONFIG_REMOTE_WAKEUP, USB_CONFIG_POWER_MA(500) }
+
+#define D_INTERFACE(_n,_numEndpoints,_class,_subClass,_protocol) \
+	{ 9, 4, _n, 0, _numEndpoints, _class,_subClass, _protocol, 0 }
+
+#define D_ENDPOINT(_addr,_attr,_packetSize, _interval) \
+	{ 7, 5, _addr,_attr,_packetSize, _interval }
+
+#define D_IAD(_firstInterface, _count, _class, _subClass, _protocol) \
+	{ 8, 11, _firstInterface, _count, _class, _subClass, _protocol, 0 }
+
+#define D_CDCCS(_subtype,_d0,_d1)	{ 5, 0x24, _subtype, _d0, _d1 }
+#define D_CDCCS4(_subtype,_d0)		{ 4, 0x24, _subtype, _d0 }
+
+// Bootloader related fields
+// Old Caterina bootloader places the MAGIC key into unsafe RAM locations (it can be rewritten
+// by the running sketch before to actual reboot).
+// Newer bootloaders, recognizable by the LUFA "signature" at the end of the flash, can handle both
+// the usafe and the safe location.
+#ifndef MAGIC_KEY
+#define MAGIC_KEY 0x7777
+#endif
+
+#ifndef MAGIC_KEY_POS
+#define MAGIC_KEY_POS 0x0800
+#endif
+
+#ifndef NEW_LUFA_SIGNATURE
+#define NEW_LUFA_SIGNATURE 0xDCFB
+#endif
+
+#endif

test/arduino_leonardo_bridge_multi_cdc/USBDesc.h

@@ -0,0 +1,77 @@
+/*
+   Copyright (c) 2011, Peter Barrett
+   Copyright (c) 2015, Arduino LLC
+
+   Permission to use, copy, modify, and/or distribute this software for
+   any purpose with or without fee is hereby granted, provided that the
+   above copyright notice and this permission notice appear in all copies.
+
+   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
+   BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
+   OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+   WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+   ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+   SOFTWARE.
+ */
+
+#define PLUGGABLE_USB_ENABLED
+
+#if defined(EPRST6)
+#define USB_ENDPOINTS 7 // AtMegaxxU4
+#else
+#define USB_ENDPOINTS 5 // AtMegaxxU2
+#endif
+
+#define ISERIAL_MAX_LEN     20
+
+#define CDC_INTERFACE_COUNT	2
+#define CDC_ENPOINT_COUNT	3
+
+// kai:begin
+#undef CDC_ACM_INTERFACE
+#undef CDC_DATA_INTERFACE
+#undef CDC_FIRST_ENDPOINT
+#undef CDC_ENDPOINT_ACM
+#undef CDC_ENDPOINT_OUT
+#undef CDC_ENDPOINT_IN
+#undef CDC_RX
+#undef CDC_TX
+
+#define CDC_ACM_INTERFACE1	0	// CDC ACM
+#define CDC_DATA_INTERFACE1	1	// CDC Data
+#define CDC_FIRST_ENDPOINT1	1
+#define CDC_ENDPOINT_ACM1	(CDC_FIRST_ENDPOINT1)							// CDC First
+#define CDC_ENDPOINT_OUT1	(CDC_FIRST_ENDPOINT1+1)
+#define CDC_ENDPOINT_IN1		(CDC_FIRST_ENDPOINT1+2)
+
+#define CDC_ACM_INTERFACE2  2 // CDC ACM
+#define CDC_DATA_INTERFACE2  3 // CDC Data
+#define CDC_FIRST_ENDPOINT2  4 
+#define CDC_ENDPOINT_ACM2  (CDC_FIRST_ENDPOINT2)              // CDC First
+#define CDC_ENDPOINT_OUT2  (CDC_FIRST_ENDPOINT2+1)
+#define CDC_ENDPOINT_IN2  (CDC_FIRST_ENDPOINT2+2)
+
+// only one of both interfaces is functional:
+#define ACTIVE_INTERFACE 1
+
+#if ACTIVE_INTERFACE == 1
+# define CDC_CLASS_INTERFACE CDC_ACM_INTERFACE1
+# define CDC_RX              CDC_ENDPOINT_OUT1
+# define CDC_TX              CDC_ENDPOINT_IN1
+#else
+# define CDC_CLASS_INTERFACE CDC_ACM_INTERFACE2
+# define CDC_RX              CDC_ENDPOINT_OUT2
+# define CDC_TX              CDC_ENDPOINT_IN2
+#endif
+
+#undef USB_VID
+#define USB_VID 0x2342
+// kai:end
+
+#define INTERFACE_COUNT    (MSC_INTERFACE + MSC_INTERFACE_COUNT)
+
+#define IMANUFACTURER   1
+#define IPRODUCT        2
+#define ISERIAL         3

test/arduino_leonardo_bridge_multi_cdc/arduino_leonardo_bridge_multi_cdc.ino

@@ -0,0 +1,64 @@
+/*
+  bridge USB-serial to hardware-serial
+
+  for Arduinos based on ATmega32u4 (Leonardo and compatible Pro Micro, Micro)
+  hardware serial is configured with baud-rate, databits, stopbits, parity as send over USB
+
+  see https://github.com/arduino/Arduino/tree/master/hardware/arduino/avr/cores/arduino 
+  -> CDC.cpp|HardwareSerial.cpp for serial implementation details
+
+  this sketch is mainly for demonstration / test of CDC communication
+  performance as real usb-serial bridge would be inacceptable as each byte is send in separate USB packet
+*/
+
+uint32_t baud = 9600;
+uint8_t databits = 8;
+uint8_t stopbits = 1;
+uint8_t parity = 0;
+
+void setup() {
+  Serial.begin(baud); // USB
+  Serial1.begin(baud, SERIAL_8N1);
+}
+
+void loop() {
+  // show USB connected state
+  if (Serial) TXLED1;
+  else        TXLED0;
+
+  // configure hardware serial
+  if (Serial.baud() != baud ||
+      Serial.numbits() != databits ||
+      Serial.stopbits() != stopbits ||
+      Serial.paritytype() != parity) {
+    baud = Serial.baud();
+    databits = Serial.numbits();
+    stopbits = Serial.stopbits();
+    parity = Serial.paritytype();
+    uint8_t config = 0; // ucsrc register
+    switch (databits) {
+      case 5: break;
+      case 6: config |= 2; break;
+      case 7: config |= 4; break;
+      case 8: config |= 6; break;
+      default: config |= 6;
+    }
+    switch (stopbits) {
+      case 2: config |= 8;
+        // 1.5 stopbits not supported
+    }
+    switch (parity) {
+      case 1: config |= 0x30; break; // odd
+      case 2: config |= 0x20; break; // even
+        // mark, space not supported
+    }
+    Serial1.end();
+    Serial1.begin(baud, config);
+  }
+
+  // bridge
+  if (Serial.available() > 0)
+    Serial1.write(Serial.read());
+  if (Serial1.available() > 0)
+    Serial.write(Serial1.read());
+}

test/pi_pico/README.md

@@ -0,0 +1,6 @@
+
+# `tinyusb_dev_cdc_dual_ports.uf2`
+
+compiled from `C:/Program Files/Raspberry Pi/Pico SDK v1.5.1/pico-sdk/lib/tinyusb/examples/device/cdc_dual_ports`
+to `C:/Users/` _user_`/Documents/Pico-v1.5.1/pico-examples/build/usb/device/tinyusb_device_examples/cdc_dual_ports/tinyusb_dev_cdc_dual_ports.uf2`
+

test/serial_test/serial_test.ino

@@ -1,43 +0,0 @@
-/* Copyright 2012 Google Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
- * Project home page: http://code.google.com/p/usb-serial-for-android/
- */
-
-// Sample Arduino sketch for use with usb-serial-for-android.
-// Prints an ever-increasing counter, and writes back anything
-// it receives.
-
-static int counter = 0;
-void setup() {
-  Serial.begin(115200);
-}
-
-void loop() {
-  Serial.print("Tick #");
-  Serial.print(counter++, DEC);
-  Serial.print("\n");
-
-  if (Serial.peek() != -1) {
-    Serial.print("Read: ");
-    do {
-      Serial.print((char) Serial.read());
-    } while (Serial.peek() != -1);
-    Serial.print("\n");
-  }
-  delay(1000);
-}

usbSerialExamples/build.gradle

@@ -1,14 +1,21 @@
-apply plugin: 'com.android.application'
+plugins {
+    id 'com.android.application'
+}
 
 android {
-    compileSdkVersion 28
-    buildToolsVersion '28.0.3'
+    compileSdkVersion 35
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 
     defaultConfig {
         minSdkVersion 17
-        targetSdkVersion 28
+        targetSdkVersion 35
+        vectorDrawables.useSupportLibrary = true
 
-        testInstrumentationRunner "android.test.InstrumentationTestRunner"
+        missingDimensionStrategy 'device', 'anyDevice'
     }
 
     buildTypes {
@@ -16,8 +23,11 @@ android {
             minifyEnabled true
         }
     }
+    namespace 'com.hoho.android.usbserial.examples'
 }
 
 dependencies {
     implementation project(':usbSerialForAndroid')
+    implementation 'androidx.appcompat:appcompat:1.6.1' // later versions have minsdk 21
+    implementation 'com.google.android.material:material:1.11.0' // later versions have minsdk 19
 }

usbSerialExamples/src/main/AndroidManifest.xml

@@ -1,37 +1,32 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.hoho.android.usbserial.examples"
-    android:versionCode="1"
-    android:versionName="1.0" >
-
-    <uses-feature android:name="android.hardware.usb.host" />
+    xmlns:tools="http://schemas.android.com/tools">
 
+    <!-- mipmap/ic_launcher created with Android Studio -> New -> Image Asset using @color/colorPrimary and USB clip art -->
     <application
-        android:icon="@drawable/ic_launcher"
-        android:label="@string/app_name" >
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:theme="@style/AppTheme"
+        tools:ignore="AllowBackup,GoogleAppIndexingWarning">
+        <!-- for this simple app launchMode=singleTask and singleTop have same effect.
+             If you would start another activity in the app, e.g. Android Settings
+             then you should use singleTask, else a new MainActivity would be started
+             when the settings activity is currently shown -->
         <activity
-            android:name="com.hoho.android.usbserial.examples.DeviceListActivity"
-            android:label="@string/app_name"
-            android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen" >
+            android:name=".MainActivity"
+            android:launchMode="singleTask"
+            android:windowSoftInputMode="stateHidden|adjustResize"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
-
-                <category android:name="android.intent.category.DEFAULT" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
             </intent-filter>
-
             <meta-data
                 android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
                 android:resource="@xml/device_filter" />
         </activity>
-        <activity
-            android:name="com.hoho.android.usbserial.examples.SerialConsoleActivity"
-            android:label="@string/app_name"
-            android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen" >
-        </activity>
     </application>
-
-</manifest>
+</manifest>

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/CustomProber.java

@@ -0,0 +1,22 @@
+package com.hoho.android.usbserial.examples;
+
+import com.hoho.android.usbserial.driver.FtdiSerialDriver;
+import com.hoho.android.usbserial.driver.ProbeTable;
+import com.hoho.android.usbserial.driver.UsbSerialProber;
+
+/**
+ * add devices here, that are not known to DefaultProber
+ *
+ * if the App should auto start for these devices, also
+ * add IDs to app/src/main/res/xml/device_filter.xml
+ */
+class CustomProber {
+
+    static UsbSerialProber getCustomProber() {
+        ProbeTable customTable = new ProbeTable();
+        customTable.addProduct(0x1234, 0x0001, FtdiSerialDriver.class); // e.g. device with custom VID+PID
+        customTable.addProduct(0x1234, 0x0002, FtdiSerialDriver.class); // e.g. device with custom VID+PID
+        return new UsbSerialProber(customTable);
+    }
+
+}

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/DeviceListActivity.java

@@ -1,206 +0,0 @@
-/* Copyright 2011-2013 Google Inc.
- * Copyright 2013 mike wakerly <opensource@hoho.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
- * Project home page: https://github.com/mik3y/usb-serial-for-android
- */
-
-package com.hoho.android.usbserial.examples;
-
-import android.app.Activity;
-import android.content.Context;
-import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbManager;
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.os.Handler;
-import android.os.Message;
-import android.os.SystemClock;
-import android.util.Log;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.ArrayAdapter;
-import android.widget.ListView;
-import android.widget.ProgressBar;
-import android.widget.TextView;
-import android.widget.TwoLineListItem;
-
-import com.hoho.android.usbserial.driver.UsbSerialDriver;
-import com.hoho.android.usbserial.driver.UsbSerialPort;
-import com.hoho.android.usbserial.driver.UsbSerialProber;
-import com.hoho.android.usbserial.util.HexDump;
-
-import java.util.ArrayList;
-import java.util.List;
-
-/**
- * Shows a {@link ListView} of available USB devices.
- *
- * @author mike wakerly (opensource@hoho.com)
- */
-public class DeviceListActivity extends Activity {
-
-    private final String TAG = DeviceListActivity.class.getSimpleName();
-
-    private UsbManager mUsbManager;
-    private ListView mListView;
-    private TextView mProgressBarTitle;
-    private ProgressBar mProgressBar;
-
-    private static final int MESSAGE_REFRESH = 101;
-    private static final long REFRESH_TIMEOUT_MILLIS = 5000;
-
-    private final Handler mHandler = new Handler() {
-        @Override
-        public void handleMessage(Message msg) {
-            switch (msg.what) {
-                case MESSAGE_REFRESH:
-                    refreshDeviceList();
-                    mHandler.sendEmptyMessageDelayed(MESSAGE_REFRESH, REFRESH_TIMEOUT_MILLIS);
-                    break;
-                default:
-                    super.handleMessage(msg);
-                    break;
-            }
-        }
-
-    };
-
-    private List<UsbSerialPort> mEntries = new ArrayList<UsbSerialPort>();
-    private ArrayAdapter<UsbSerialPort> mAdapter;
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setContentView(R.layout.main);
-
-        mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
-        mListView = (ListView) findViewById(R.id.deviceList);
-        mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
-        mProgressBarTitle = (TextView) findViewById(R.id.progressBarTitle);
-
-        mAdapter = new ArrayAdapter<UsbSerialPort>(this,
-                android.R.layout.simple_expandable_list_item_2, mEntries) {
-            @Override
-            public View getView(int position, View convertView, ViewGroup parent) {
-                final TwoLineListItem row;
-                if (convertView == null){
-                    final LayoutInflater inflater =
-                            (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
-                    row = (TwoLineListItem) inflater.inflate(android.R.layout.simple_list_item_2, null);
-                } else {
-                    row = (TwoLineListItem) convertView;
-                }
-
-                final UsbSerialPort port = mEntries.get(position);
-                final UsbSerialDriver driver = port.getDriver();
-                final UsbDevice device = driver.getDevice();
-
-                final String title = String.format("Vendor %s Product %s",
-                        HexDump.toHexString((short) device.getVendorId()),
-                        HexDump.toHexString((short) device.getProductId()));
-                row.getText1().setText(title);
-
-                final String subtitle = driver.getClass().getSimpleName();
-                row.getText2().setText(subtitle);
-
-                return row;
-            }
-
-        };
-        mListView.setAdapter(mAdapter);
-
-        mListView.setOnItemClickListener(new ListView.OnItemClickListener() {
-            @Override
-            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-                Log.d(TAG, "Pressed item " + position);
-                if (position >= mEntries.size()) {
-                    Log.w(TAG, "Illegal position.");
-                    return;
-                }
-
-                final UsbSerialPort port = mEntries.get(position);
-                showConsoleActivity(port);
-            }
-        });
-    }
-
-    @Override
-    protected void onResume() {
-        super.onResume();
-        mHandler.sendEmptyMessage(MESSAGE_REFRESH);
-    }
-
-    @Override
-    protected void onPause() {
-        super.onPause();
-        mHandler.removeMessages(MESSAGE_REFRESH);
-    }
-
-    private void refreshDeviceList() {
-        showProgressBar();
-
-        new AsyncTask<Void, Void, List<UsbSerialPort>>() {
-            @Override
-            protected List<UsbSerialPort> doInBackground(Void... params) {
-                Log.d(TAG, "Refreshing device list ...");
-                SystemClock.sleep(1000);
-
-                final List<UsbSerialDriver> drivers =
-                        UsbSerialProber.getDefaultProber().findAllDrivers(mUsbManager);
-
-                final List<UsbSerialPort> result = new ArrayList<UsbSerialPort>();
-                for (final UsbSerialDriver driver : drivers) {
-                    final List<UsbSerialPort> ports = driver.getPorts();
-                    Log.d(TAG, String.format("+ %s: %s port%s",
-                            driver, Integer.valueOf(ports.size()), ports.size() == 1 ? "" : "s"));
-                    result.addAll(ports);
-                }
-
-                return result;
-            }
-
-            @Override
-            protected void onPostExecute(List<UsbSerialPort> result) {
-                mEntries.clear();
-                mEntries.addAll(result);
-                mAdapter.notifyDataSetChanged();
-                mProgressBarTitle.setText(
-                        String.format("%s device(s) found",Integer.valueOf(mEntries.size())));
-                hideProgressBar();
-                Log.d(TAG, "Done refreshing, " + mEntries.size() + " entries found.");
-            }
-
-        }.execute((Void) null);
-    }
-
-    private void showProgressBar() {
-        mProgressBar.setVisibility(View.VISIBLE);
-        mProgressBarTitle.setText(R.string.refreshing);
-    }
-
-    private void hideProgressBar() {
-        mProgressBar.setVisibility(View.INVISIBLE);
-    }
-
-    private void showConsoleActivity(UsbSerialPort port) {
-        SerialConsoleActivity.show(this, port);
-    }
-
-}

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/DevicesFragment.java

@@ -0,0 +1,164 @@
+package com.hoho.android.usbserial.examples;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbManager;
+import android.os.Bundle;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.ListFragment;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.ListView;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import com.hoho.android.usbserial.driver.UsbSerialDriver;
+import com.hoho.android.usbserial.driver.UsbSerialProber;
+
+import java.util.ArrayList;
+import java.util.Locale;
+
+public class DevicesFragment extends ListFragment {
+
+    static class ListItem {
+        UsbDevice device;
+        int port;
+        UsbSerialDriver driver;
+
+        ListItem(UsbDevice device, int port, UsbSerialDriver driver) {
+            this.device = device;
+            this.port = port;
+            this.driver = driver;
+        }
+    }
+
+    private final ArrayList<ListItem> listItems = new ArrayList<>();
+    private ArrayAdapter<ListItem> listAdapter;
+    private int baudRate = 19200;
+    private boolean withIoManager = true;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setHasOptionsMenu(true);
+        listAdapter = new ArrayAdapter<ListItem>(getActivity(), 0, listItems) {
+            @NonNull
+            @Override
+            public View getView(int position, View view, @NonNull ViewGroup parent) {
+                ListItem item = listItems.get(position);
+                if (view == null)
+                    view = getActivity().getLayoutInflater().inflate(R.layout.device_list_item, parent, false);
+                TextView text1 = view.findViewById(R.id.text1);
+                TextView text2 = view.findViewById(R.id.text2);
+                if(item.driver == null)
+                    text1.setText("<no driver>");
+                else if(item.driver.getPorts().size() == 1)
+                    text1.setText(item.driver.getClass().getSimpleName().replace("SerialDriver",""));
+                else
+                    text1.setText(item.driver.getClass().getSimpleName().replace("SerialDriver","")+", Port "+item.port);
+                text2.setText(String.format(Locale.US, "Vendor %04X, Product %04X", item.device.getVendorId(), item.device.getProductId()));
+                return view;
+            }
+        };
+    }
+
+    @Override
+    public void onActivityCreated(Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+        setListAdapter(null);
+        View header = getActivity().getLayoutInflater().inflate(R.layout.device_list_header, null, false);
+        getListView().addHeaderView(header, null, false);
+        setEmptyText("<no USB devices found>");
+        ((TextView) getListView().getEmptyView()).setTextSize(18);
+        setListAdapter(listAdapter);
+    }
+
+    @Override
+    public void onCreateOptionsMenu(@NonNull Menu menu, MenuInflater inflater) {
+        inflater.inflate(R.menu.menu_devices, menu);
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        refresh();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        int id = item.getItemId();
+        if(id == R.id.refresh) {
+            refresh();
+            return true;
+        } else if (id ==R.id.baud_rate) {
+            final String[] values = getResources().getStringArray(R.array.baud_rates);
+            int pos = java.util.Arrays.asList(values).indexOf(String.valueOf(baudRate));
+            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
+            builder.setTitle("Baud rate");
+            builder.setSingleChoiceItems(values, pos, (dialog, which) -> {
+                baudRate = Integer.parseInt(values[which]);
+                dialog.dismiss();
+            });
+            builder.create().show();
+            return true;
+        } else if (id ==R.id.read_mode) {
+            final String[] values = getResources().getStringArray(R.array.read_modes);
+            int pos = withIoManager ? 0 : 1; // read_modes[0]=event/io-manager, read_modes[1]=direct
+            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
+            builder.setTitle("Read mode");
+            builder.setSingleChoiceItems(values, pos, (dialog, which) -> {
+                withIoManager = (which == 0);
+                dialog.dismiss();
+            });
+            builder.create().show();
+            return true;
+        } else {
+            return super.onOptionsItemSelected(item);
+        }
+    }
+
+    void refresh() {
+        UsbManager usbManager = (UsbManager) getActivity().getSystemService(Context.USB_SERVICE);
+        UsbSerialProber usbDefaultProber = UsbSerialProber.getDefaultProber();
+        UsbSerialProber usbCustomProber = CustomProber.getCustomProber();
+        listItems.clear();
+        for(UsbDevice device : usbManager.getDeviceList().values()) {
+            UsbSerialDriver driver = usbDefaultProber.probeDevice(device);
+            if(driver == null) {
+                driver = usbCustomProber.probeDevice(device);
+            }
+            if(driver != null) {
+                for(int port = 0; port < driver.getPorts().size(); port++)
+                    listItems.add(new ListItem(device, port, driver));
+            } else {
+                listItems.add(new ListItem(device, 0, null));
+            }
+        }
+        listAdapter.notifyDataSetChanged();
+    }
+
+    @Override
+    public void onListItemClick(@NonNull ListView l, @NonNull View v, int position, long id) {
+        ListItem item = listItems.get(position-1);
+        if(item.driver == null) {
+            Toast.makeText(getActivity(), "no driver", Toast.LENGTH_SHORT).show();
+        } else {
+            Bundle args = new Bundle();
+            args.putInt("device", item.device.getDeviceId());
+            args.putInt("port", item.port);
+            args.putInt("baud", baudRate);
+            args.putBoolean("withIoManager", withIoManager);
+            Fragment fragment = new TerminalFragment();
+            fragment.setArguments(args);
+            getFragmentManager().beginTransaction().replace(R.id.fragment, fragment, "terminal").addToBackStack(null).commit();
+        }
+    }
+
+}

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/MainActivity.java

@@ -0,0 +1,45 @@
+package com.hoho.android.usbserial.examples;
+
+import android.content.Intent;
+import android.os.Bundle;
+import androidx.fragment.app.FragmentManager;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+
+public class MainActivity extends AppCompatActivity implements FragmentManager.OnBackStackChangedListener {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        Toolbar toolbar = findViewById(R.id.toolbar);
+        setSupportActionBar(toolbar);
+        getSupportFragmentManager().addOnBackStackChangedListener(this);
+        if (savedInstanceState == null)
+            getSupportFragmentManager().beginTransaction().add(R.id.fragment, new DevicesFragment(), "devices").commit();
+        else
+            onBackStackChanged();
+    }
+
+    @Override
+    public void onBackStackChanged() {
+        getSupportActionBar().setDisplayHomeAsUpEnabled(getSupportFragmentManager().getBackStackEntryCount()>0);
+    }
+
+    @Override
+    public boolean onSupportNavigateUp() {
+        onBackPressed();
+        return true;
+    }
+
+    @Override
+    protected void onNewIntent(Intent intent) {
+        if("android.hardware.usb.action.USB_DEVICE_ATTACHED".equals(intent.getAction())) {
+            TerminalFragment terminal = (TerminalFragment)getSupportFragmentManager().findFragmentByTag("terminal");
+            if (terminal != null)
+                terminal.status("USB device detected");
+        }
+        super.onNewIntent(intent);
+    }
+
+}

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/SerialConsoleActivity.java

@@ -1,230 +0,0 @@
-/* Copyright 2011-2013 Google Inc.
- * Copyright 2013 mike wakerly <opensource@hoho.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
- * Project home page: https://github.com/mik3y/usb-serial-for-android
- */
-
-package com.hoho.android.usbserial.examples;
-
-import android.app.Activity;
-import android.content.Context;
-import android.content.Intent;
-import android.hardware.usb.UsbDeviceConnection;
-import android.hardware.usb.UsbManager;
-import android.os.Bundle;
-import android.util.Log;
-import android.widget.CheckBox;
-import android.widget.CompoundButton;
-import android.widget.ScrollView;
-import android.widget.TextView;
-
-import com.hoho.android.usbserial.driver.UsbSerialPort;
-import com.hoho.android.usbserial.util.HexDump;
-import com.hoho.android.usbserial.util.SerialInputOutputManager;
-
-import java.io.IOException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-
-/**
- * Monitors a single {@link UsbSerialPort} instance, showing all data
- * received.
- *
- * @author mike wakerly (opensource@hoho.com)
- */
-public class SerialConsoleActivity extends Activity {
-
-    private final String TAG = SerialConsoleActivity.class.getSimpleName();
-
-    /**
-     * Driver instance, passed in statically via
-     * {@link #show(Context, UsbSerialPort)}.
-     *
-     * <p/>
-     * This is a devious hack; it'd be cleaner to re-create the driver using
-     * arguments passed in with the {@link #startActivity(Intent)} intent. We
-     * can get away with it because both activities will run in the same
-     * process, and this is a simple demo.
-     */
-    private static UsbSerialPort sPort = null;
-
-    private TextView mTitleTextView;
-    private TextView mDumpTextView;
-    private ScrollView mScrollView;
-    private CheckBox chkDTR;
-    private CheckBox chkRTS;
-
-    private final ExecutorService mExecutor = Executors.newSingleThreadExecutor();
-
-    private SerialInputOutputManager mSerialIoManager;
-
-    private final SerialInputOutputManager.Listener mListener =
-            new SerialInputOutputManager.Listener() {
-
-        @Override
-        public void onRunError(Exception e) {
-            Log.d(TAG, "Runner stopped.");
-        }
-
-        @Override
-        public void onNewData(final byte[] data) {
-            SerialConsoleActivity.this.runOnUiThread(new Runnable() {
-                @Override
-                public void run() {
-                    SerialConsoleActivity.this.updateReceivedData(data);
-                }
-            });
-        }
-    };
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setContentView(R.layout.serial_console);
-        mTitleTextView = (TextView) findViewById(R.id.demoTitle);
-        mDumpTextView = (TextView) findViewById(R.id.consoleText);
-        mScrollView = (ScrollView) findViewById(R.id.demoScroller);
-        chkDTR = (CheckBox) findViewById(R.id.checkBoxDTR);
-        chkRTS = (CheckBox) findViewById(R.id.checkBoxRTS);
-
-        chkDTR.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
-            @Override
-            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
-                try {
-                    sPort.setDTR(isChecked);
-                }catch (IOException x){}
-            }
-        });
-
-        chkRTS.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
-            @Override
-            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
-                try {
-                    sPort.setRTS(isChecked);
-                }catch (IOException x){}
-            }
-        });
-
-    }
-
-
-    @Override
-    protected void onPause() {
-        super.onPause();
-        stopIoManager();
-        if (sPort != null) {
-            try {
-                sPort.close();
-            } catch (IOException e) {
-                // Ignore.
-            }
-            sPort = null;
-        }
-        finish();
-    }
-
-    void showStatus(TextView theTextView, String theLabel, boolean theValue){
-        String msg = theLabel + ": " + (theValue ? "enabled" : "disabled") + "\n";
-        theTextView.append(msg);
-    }
-
-    @Override
-    protected void onResume() {
-        super.onResume();
-        Log.d(TAG, "Resumed, port=" + sPort);
-        if (sPort == null) {
-            mTitleTextView.setText("No serial device.");
-        } else {
-            final UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
-
-            UsbDeviceConnection connection = usbManager.openDevice(sPort.getDriver().getDevice());
-            if (connection == null) {
-                mTitleTextView.setText("Opening device failed");
-                return;
-            }
-
-            try {
-                sPort.open(connection);
-                sPort.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
-
-                showStatus(mDumpTextView, "CD  - Carrier Detect", sPort.getCD());
-                showStatus(mDumpTextView, "CTS - Clear To Send", sPort.getCTS());
-                showStatus(mDumpTextView, "DSR - Data Set Ready", sPort.getDSR());
-                showStatus(mDumpTextView, "DTR - Data Terminal Ready", sPort.getDTR());
-                showStatus(mDumpTextView, "DSR - Data Set Ready", sPort.getDSR());
-                showStatus(mDumpTextView, "RI  - Ring Indicator", sPort.getRI());
-                showStatus(mDumpTextView, "RTS - Request To Send", sPort.getRTS());
-
-            } catch (IOException e) {
-                Log.e(TAG, "Error setting up device: " + e.getMessage(), e);
-                mTitleTextView.setText("Error opening device: " + e.getMessage());
-                try {
-                    sPort.close();
-                } catch (IOException e2) {
-                    // Ignore.
-                }
-                sPort = null;
-                return;
-            }
-            mTitleTextView.setText("Serial device: " + sPort.getClass().getSimpleName());
-        }
-        onDeviceStateChange();
-    }
-
-    private void stopIoManager() {
-        if (mSerialIoManager != null) {
-            Log.i(TAG, "Stopping io manager ..");
-            mSerialIoManager.stop();
-            mSerialIoManager = null;
-        }
-    }
-
-    private void startIoManager() {
-        if (sPort != null) {
-            Log.i(TAG, "Starting io manager ..");
-            mSerialIoManager = new SerialInputOutputManager(sPort, mListener);
-            mExecutor.submit(mSerialIoManager);
-        }
-    }
-
-    private void onDeviceStateChange() {
-        stopIoManager();
-        startIoManager();
-    }
-
-    private void updateReceivedData(byte[] data) {
-        final String message = "Read " + data.length + " bytes: \n"
-                + HexDump.dumpHexString(data) + "\n\n";
-        mDumpTextView.append(message);
-        mScrollView.smoothScrollTo(0, mDumpTextView.getBottom());
-    }
-
-    /**
-     * Starts the activity, using the supplied driver instance.
-     *
-     * @param context
-     * @param driver
-     */
-    static void show(Context context, UsbSerialPort port) {
-        sPort = port;
-        final Intent intent = new Intent(context, SerialConsoleActivity.class);
-        intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_NO_HISTORY);
-        context.startActivity(intent);
-    }
-
-}

usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/TerminalFragment.java

@@ -0,0 +1,409 @@
+package com.hoho.android.usbserial.examples;
+
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbManager;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
+import android.text.Spannable;
+import android.text.SpannableStringBuilder;
+import android.text.method.ScrollingMovementMethod;
+import android.text.style.ForegroundColorSpan;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+import android.widget.Toast;
+import android.widget.ToggleButton;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import androidx.fragment.app.Fragment;
+
+import com.hoho.android.usbserial.driver.UsbSerialDriver;
+import com.hoho.android.usbserial.driver.UsbSerialPort;
+import com.hoho.android.usbserial.driver.UsbSerialProber;
+import com.hoho.android.usbserial.util.HexDump;
+import com.hoho.android.usbserial.util.SerialInputOutputManager;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.EnumSet;
+
+public class TerminalFragment extends Fragment implements SerialInputOutputManager.Listener {
+
+    private enum UsbPermission { Unknown, Requested, Granted, Denied }
+
+    private static final String INTENT_ACTION_GRANT_USB = BuildConfig.APPLICATION_ID + ".GRANT_USB";
+    private static final int WRITE_WAIT_MILLIS = 2000;
+    private static final int READ_WAIT_MILLIS = 2000;
+
+    private int deviceId, portNum, baudRate;
+    private boolean withIoManager;
+
+    private final BroadcastReceiver broadcastReceiver;
+    private final Handler mainLooper;
+    private TextView receiveText;
+    private ControlLines controlLines;
+
+    private SerialInputOutputManager usbIoManager;
+    private UsbSerialPort usbSerialPort;
+    private UsbPermission usbPermission = UsbPermission.Unknown;
+    private boolean connected = false;
+
+    public TerminalFragment() {
+        broadcastReceiver = new BroadcastReceiver() {
+            @Override
+            public void onReceive(Context context, Intent intent) {
+                if(INTENT_ACTION_GRANT_USB.equals(intent.getAction())) {
+                    usbPermission = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)
+                            ? UsbPermission.Granted : UsbPermission.Denied;
+                    connect();
+                }
+            }
+        };
+        mainLooper = new Handler(Looper.getMainLooper());
+    }
+
+    /*
+     * Lifecycle
+     */
+    @Override
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setHasOptionsMenu(true);
+        setRetainInstance(true);
+        deviceId = getArguments().getInt("device");
+        portNum = getArguments().getInt("port");
+        baudRate = getArguments().getInt("baud");
+        withIoManager = getArguments().getBoolean("withIoManager");
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+        ContextCompat.registerReceiver(getActivity(), broadcastReceiver, new IntentFilter(INTENT_ACTION_GRANT_USB), ContextCompat.RECEIVER_NOT_EXPORTED);
+    }
+
+    @Override
+    public void onStop() {
+        getActivity().unregisterReceiver(broadcastReceiver);
+        super.onStop();
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        if(!connected && (usbPermission == UsbPermission.Unknown || usbPermission == UsbPermission.Granted))
+            mainLooper.post(this::connect);
+    }
+
+    @Override
+    public void onPause() {
+        if(connected) {
+            status("disconnected");
+            disconnect();
+        }
+        super.onPause();
+    }
+
+    /*
+     * UI
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+        View view = inflater.inflate(R.layout.fragment_terminal, container, false);
+        receiveText = view.findViewById(R.id.receive_text);                          // TextView performance decreases with number of spans
+        receiveText.setTextColor(getResources().getColor(R.color.colorRecieveText)); // set as default color to reduce number of spans
+        receiveText.setMovementMethod(ScrollingMovementMethod.getInstance());
+        TextView sendText = view.findViewById(R.id.send_text);
+        View sendBtn = view.findViewById(R.id.send_btn);
+        sendBtn.setOnClickListener(v -> send(sendText.getText().toString()));
+        View receiveBtn = view.findViewById(R.id.receive_btn);
+        controlLines = new ControlLines(view);
+        if(withIoManager) {
+            receiveBtn.setVisibility(View.GONE);
+        } else {
+            receiveBtn.setOnClickListener(v -> read());
+        }
+        return view;
+    }
+
+    @Override
+    public void onCreateOptionsMenu(@NonNull Menu menu, MenuInflater inflater) {
+        inflater.inflate(R.menu.menu_terminal, menu);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        int id = item.getItemId();
+        if (id == R.id.clear) {
+            receiveText.setText("");
+            return true;
+        } else if( id == R.id.send_break) {
+            if(!connected) {
+                Toast.makeText(getActivity(), "not connected", Toast.LENGTH_SHORT).show();
+            } else {
+                try {
+                    usbSerialPort.setBreak(true);
+                    Thread.sleep(100); // should show progress bar instead of blocking UI thread
+                    usbSerialPort.setBreak(false);
+                    SpannableStringBuilder spn = new SpannableStringBuilder();
+                    spn.append("send <break>\n");
+                    spn.setSpan(new ForegroundColorSpan(getResources().getColor(R.color.colorSendText)), 0, spn.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+                    receiveText.append(spn);
+                } catch(UnsupportedOperationException ignored) {
+                    Toast.makeText(getActivity(), "BREAK not supported", Toast.LENGTH_SHORT).show();
+                } catch(Exception e) {
+                    Toast.makeText(getActivity(), "BREAK failed: " + e.getMessage(), Toast.LENGTH_SHORT).show();
+                }
+            }
+            return true;
+        } else {
+            return super.onOptionsItemSelected(item);
+        }
+    }
+
+    /*
+     * Serial
+     */
+    @Override
+    public void onNewData(byte[] data) {
+        mainLooper.post(() -> {
+            receive(data);
+        });
+    }
+
+    @Override
+    public void onRunError(Exception e) {
+        mainLooper.post(() -> {
+            status("connection lost: " + e.getMessage());
+            disconnect();
+        });
+    }
+
+    /*
+     * Serial + UI
+     */
+    private void connect() {
+        UsbDevice device = null;
+        UsbManager usbManager = (UsbManager) getActivity().getSystemService(Context.USB_SERVICE);
+        for(UsbDevice v : usbManager.getDeviceList().values())
+            if(v.getDeviceId() == deviceId)
+                device = v;
+        if(device == null) {
+            status("connection failed: device not found");
+            return;
+        }
+        UsbSerialDriver driver = UsbSerialProber.getDefaultProber().probeDevice(device);
+        if(driver == null) {
+            driver = CustomProber.getCustomProber().probeDevice(device);
+        }
+        if(driver == null) {
+            status("connection failed: no driver for device");
+            return;
+        }
+        if(portNum >= driver.getPorts().size()) {
+            status("connection failed: not enough ports at device");
+            return;
+        }
+        usbSerialPort = driver.getPorts().get(portNum);
+        UsbDeviceConnection usbConnection = usbManager.openDevice(driver.getDevice());
+        if(usbConnection == null && usbPermission == UsbPermission.Unknown && !usbManager.hasPermission(driver.getDevice())) {
+            usbPermission = UsbPermission.Requested;
+            int flags = Build.VERSION.SDK_INT >= Build.VERSION_CODES.M ? PendingIntent.FLAG_MUTABLE : 0;
+            Intent intent = new Intent(INTENT_ACTION_GRANT_USB);
+            intent.setPackage(getActivity().getPackageName());
+            PendingIntent usbPermissionIntent = PendingIntent.getBroadcast(getActivity(), 0, intent, flags);
+            usbManager.requestPermission(driver.getDevice(), usbPermissionIntent);
+            return;
+        }
+        if(usbConnection == null) {
+            if (!usbManager.hasPermission(driver.getDevice()))
+                status("connection failed: permission denied");
+            else
+                status("connection failed: open failed");
+            return;
+        }
+
+        try {
+            usbSerialPort.open(usbConnection);
+            try{
+                usbSerialPort.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
+            }catch (UnsupportedOperationException e){
+                status("unsupport setparameters");
+            }
+            if(withIoManager) {
+                usbIoManager = new SerialInputOutputManager(usbSerialPort, this);
+                usbIoManager.start();
+            }
+            status("connected");
+            connected = true;
+            controlLines.start();
+        } catch (Exception e) {
+            status("connection failed: " + e.getMessage());
+            disconnect();
+        }
+    }
+
+    private void disconnect() {
+        connected = false;
+        controlLines.stop();
+        if(usbIoManager != null) {
+            usbIoManager.setListener(null);
+            usbIoManager.stop();
+        }
+        usbIoManager = null;
+        try {
+            usbSerialPort.close();
+        } catch (IOException ignored) {}
+        usbSerialPort = null;
+    }
+
+    private void send(String str) {
+        if(!connected) {
+            Toast.makeText(getActivity(), "not connected", Toast.LENGTH_SHORT).show();
+            return;
+        }
+        try {
+        byte[] data = (str + '\n').getBytes();
+            SpannableStringBuilder spn = new SpannableStringBuilder();
+            spn.append("send " + data.length + " bytes\n");
+            spn.append(HexDump.dumpHexString(data)).append("\n");
+            spn.setSpan(new ForegroundColorSpan(getResources().getColor(R.color.colorSendText)), 0, spn.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            receiveText.append(spn);
+            usbSerialPort.write(data, WRITE_WAIT_MILLIS);
+        } catch (Exception e) {
+            onRunError(e);
+        }
+    }
+
+    private void read() {
+        if(!connected) {
+            Toast.makeText(getActivity(), "not connected", Toast.LENGTH_SHORT).show();
+            return;
+        }
+        try {
+            byte[] buffer = new byte[8192];
+            int len = usbSerialPort.read(buffer, READ_WAIT_MILLIS);
+            receive(Arrays.copyOf(buffer, len));
+        } catch (IOException e) {
+            // when using read with timeout, USB bulkTransfer returns -1 on timeout _and_ errors
+            // like connection loss, so there is typically no exception thrown here on error
+            status("connection lost: " + e.getMessage());
+            disconnect();
+        }
+    }
+
+    private void receive(byte[] data) {
+        SpannableStringBuilder spn = new SpannableStringBuilder();
+        spn.append("receive " + data.length + " bytes\n");
+        if(data.length > 0)
+            spn.append(HexDump.dumpHexString(data)).append("\n");
+        receiveText.append(spn);
+    }
+
+    void status(String str) {
+        SpannableStringBuilder spn = new SpannableStringBuilder(str+'\n');
+        spn.setSpan(new ForegroundColorSpan(getResources().getColor(R.color.colorStatusText)), 0, spn.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        receiveText.append(spn);
+    }
+
+    class ControlLines {
+        private static final int refreshInterval = 200; // msec
+
+        private final Runnable runnable;
+        private final ToggleButton rtsBtn, ctsBtn, dtrBtn, dsrBtn, cdBtn, riBtn;
+
+        ControlLines(View view) {
+            runnable = this::run; // w/o explicit Runnable, a new lambda would be created on each postDelayed, which would not be found again by removeCallbacks
+
+            rtsBtn = view.findViewById(R.id.controlLineRts);
+            ctsBtn = view.findViewById(R.id.controlLineCts);
+            dtrBtn = view.findViewById(R.id.controlLineDtr);
+            dsrBtn = view.findViewById(R.id.controlLineDsr);
+            cdBtn = view.findViewById(R.id.controlLineCd);
+            riBtn = view.findViewById(R.id.controlLineRi);
+            rtsBtn.setOnClickListener(this::toggle);
+            dtrBtn.setOnClickListener(this::toggle);
+        }
+
+        private void toggle(View v) {
+            ToggleButton btn = (ToggleButton) v;
+            if (!connected) {
+                btn.setChecked(!btn.isChecked());
+                Toast.makeText(getActivity(), "not connected", Toast.LENGTH_SHORT).show();
+                return;
+            }
+            String ctrl = "";
+            try {
+                if (btn.equals(rtsBtn)) { ctrl = "RTS"; usbSerialPort.setRTS(btn.isChecked()); }
+                if (btn.equals(dtrBtn)) { ctrl = "DTR"; usbSerialPort.setDTR(btn.isChecked()); }
+            } catch (IOException e) {
+                status("set" + ctrl + "() failed: " + e.getMessage());
+            }
+        }
+
+        private void run() {
+            if (!connected)
+                return;
+            try {
+                EnumSet<UsbSerialPort.ControlLine> controlLines = usbSerialPort.getControlLines();
+                rtsBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.RTS));
+                ctsBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.CTS));
+                dtrBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.DTR));
+                dsrBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.DSR));
+                cdBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.CD));
+                riBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.RI));
+                mainLooper.postDelayed(runnable, refreshInterval);
+            } catch (Exception e) {
+                status("getControlLines() failed: " + e.getMessage() + " -> stopped control line refresh");
+            }
+        }
+
+        void start() {
+            if (!connected)
+                return;
+            try {
+                EnumSet<UsbSerialPort.ControlLine> controlLines = usbSerialPort.getSupportedControlLines();
+                if (!controlLines.contains(UsbSerialPort.ControlLine.RTS)) rtsBtn.setVisibility(View.INVISIBLE);
+                if (!controlLines.contains(UsbSerialPort.ControlLine.CTS)) ctsBtn.setVisibility(View.INVISIBLE);
+                if (!controlLines.contains(UsbSerialPort.ControlLine.DTR)) dtrBtn.setVisibility(View.INVISIBLE);
+                if (!controlLines.contains(UsbSerialPort.ControlLine.DSR)) dsrBtn.setVisibility(View.INVISIBLE);
+                if (!controlLines.contains(UsbSerialPort.ControlLine.CD))   cdBtn.setVisibility(View.INVISIBLE);
+                if (!controlLines.contains(UsbSerialPort.ControlLine.RI))   riBtn.setVisibility(View.INVISIBLE);
+                run();
+            } catch (Exception e) {
+                Toast.makeText(getActivity(), "getSupportedControlLines() failed: " + e.getMessage(), Toast.LENGTH_SHORT).show();
+                rtsBtn.setVisibility(View.INVISIBLE);
+                ctsBtn.setVisibility(View.INVISIBLE);
+                dtrBtn.setVisibility(View.INVISIBLE);
+                dsrBtn.setVisibility(View.INVISIBLE);
+                cdBtn.setVisibility(View.INVISIBLE);
+                cdBtn.setVisibility(View.INVISIBLE);
+                riBtn.setVisibility(View.INVISIBLE);
+            }
+        }
+
+        void stop() {
+            mainLooper.removeCallbacks(runnable);
+            rtsBtn.setChecked(false);
+            ctsBtn.setChecked(false);
+            dtrBtn.setChecked(false);
+            dsrBtn.setChecked(false);
+            cdBtn.setChecked(false);
+            riBtn.setChecked(false);
+        }
+    }
+}

usbSerialExamples/src/main/res/drawable/ic_delete_white_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FFFFFFFF"
+        android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z"/>
+</vector>

usbSerialExamples/src/main/res/drawable/ic_send_white_24dp.xml

@@ -0,0 +1,9 @@
+<vector  xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FFFFFFFF"
+        android:pathData="M2.01,21L23,12 2.01,3 2,10l15,2 -15,2z"/>
+</vector>

usbSerialExamples/src/main/res/layout/activity_main.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+
+    <com.google.android.material.appbar.AppBarLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <androidx.appcompat.widget.Toolbar
+            android:id="@+id/toolbar"
+            android:layout_width="match_parent"
+            android:layout_height="?attr/actionBarSize"
+            android:background="?attr/colorPrimary" />
+
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <RelativeLayout
+        android:id="@+id/fragment"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

usbSerialExamples/src/main/res/layout/device_list_header.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:background="?android:attr/listDivider"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="12dp"
+        android:layout_marginBottom="12dp"
+        android:gravity="center"
+        android:text="@string/devices"
+        android:textAppearance="@style/TextAppearance.AppCompat.Medium" />
+</LinearLayout>

usbSerialExamples/src/main/res/layout/device_list_item.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/text1"
+        android:layout_marginTop="12dp"
+        android:layout_marginStart="12dp"
+        android:layout_marginEnd="12dp"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="@style/TextAppearance.AppCompat.Medium" />
+
+    <TextView
+        android:id="@+id/text2"
+        android:layout_marginStart="20dp"
+        android:layout_marginEnd="20dp"
+        android:layout_marginBottom="12dp"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="@style/TextAppearance.AppCompat.Small" />
+
+</LinearLayout>

usbSerialExamples/src/main/res/layout/fragment_terminal.xml

@@ -0,0 +1,128 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <ToggleButton
+            android:id="@+id/controlLineRts"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:minWidth="48sp"
+            android:textOff="RTS"
+            android:textOn="RTS" />
+
+        <ToggleButton
+            android:id="@+id/controlLineCts"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:minWidth="48sp"
+            android:clickable="false"
+            android:textColor="@android:color/secondary_text_dark"
+            android:textOff="CTS"
+            android:textOn="CTS" />
+
+        <View
+            android:layout_height="match_parent"
+            android:layout_width="6dp" />
+
+        <ToggleButton
+            android:id="@+id/controlLineDtr"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:minWidth="48sp"
+            android:textOff="DTR"
+            android:textOn="DTR" />
+
+        <ToggleButton
+            android:id="@+id/controlLineDsr"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:clickable="false"
+            android:minWidth="48sp"
+            android:textColor="@android:color/secondary_text_dark"
+            android:textOff="DSR"
+            android:textOn="DSR" />
+
+        <View
+            android:layout_height="match_parent"
+            android:layout_width="6dp" />
+
+        <ToggleButton
+            android:id="@+id/controlLineCd"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:clickable="false"
+            android:minWidth="48sp"
+            android:textColor="@android:color/secondary_text_dark"
+            android:textOff="CD"
+            android:textOn="CD" />
+
+        <ToggleButton
+            android:id="@+id/controlLineRi"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:minWidth="48sp"
+            android:clickable="false"
+            android:textColor="@android:color/secondary_text_dark"
+            android:textOff="RI"
+            android:textOn="RI" />
+
+    </LinearLayout>
+
+    <View
+        android:layout_width="match_parent"
+        android:background="?android:attr/listDivider"
+        android:layout_height="2dp" />
+
+    <TextView
+        android:id="@+id/receive_text"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1"
+        android:freezesText="true"
+        android:gravity="bottom"
+        android:scrollbars="vertical"
+        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
+        android:typeface="monospace" />
+
+    <Button
+        android:id="@+id/receive_btn"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Read" />
+
+    <View
+        android:layout_width="match_parent"
+        android:background="?android:attr/listDivider"
+        android:layout_height="2dp" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <EditText
+            android:id="@+id/send_text"
+            android:layout_width="0dp"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:inputType="text|textNoSuggestions"
+            android:singleLine="true" />
+
+        <ImageButton
+            android:id="@+id/send_btn"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:srcCompat="@drawable/ic_send_white_24dp" />
+    </LinearLayout>
+
+</LinearLayout>
+

usbSerialExamples/src/main/res/layout/main.xml

@@ -1,50 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent" >
-
-    <TextView
-        android:id="@+id/demoTitle"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_alignParentTop="true"
-        android:layout_centerHorizontal="true"
-        android:text="@string/app_title"
-        android:textSize="24sp"
-        android:textStyle="bold" />
-
-    <TextView
-        android:id="@+id/progressBarTitle"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_below="@+id/demoTitle"
-        android:layout_centerHorizontal="true"
-        android:text="@string/refreshing"
-        android:padding="8dp"
-        android:textSize="18sp" />
-    
-    <ProgressBar
-        android:id="@+id/progressBar"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_below="@+id/progressBarTitle"
-        android:layout_centerHorizontal="true"
-        android:padding="8dp"
-        style="@android:style/Widget.Holo.ProgressBar.Horizontal"
-        android:indeterminate="true" />
-    
-    <View
-        android:id="@+id/separator"
-        android:layout_width="match_parent"
-        android:layout_height="1dip"
-        android:layout_below="@+id/progressBar"
-        android:layout_centerHorizontal="true"
-        android:background="#eeeeee" />
-
-    <ListView
-        android:id="@+id/deviceList"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_below="@+id/separator" />
-
-</RelativeLayout>

usbSerialExamples/src/main/res/layout/serial_console.xml

@@ -1,54 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:orientation="vertical"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent" >
-    <TextView
-        android:id="@+id/demoTitle"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_alignParentTop="true"
-        android:text="@string/app_title"
-        android:textSize="24sp"
-        android:textStyle="bold" />
-
-    <View
-        android:id="@+id/separator"
-        android:layout_width="match_parent"
-        android:layout_height="1dip"
-        android:background="#eeeeee" />
-
-    <CheckBox
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="@string/textBtnDTR"
-        android:id="@+id/checkBoxDTR" />
-
-
-    <CheckBox
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="@string/textBtnRTS"
-        android:id="@+id/checkBoxRTS" />
-
-    <View
-        android:id="@+id/separator2"
-        android:layout_width="match_parent"
-        android:layout_below="@+id/demoTitle"
-        android:layout_height="1dip"
-        android:background="#eeeeee" />
-
-    <ScrollView
-        android:id="@+id/demoScroller"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-         >
-
-        <TextView
-            android:id="@+id/consoleText"
-            android:textIsSelectable="true"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:typeface="monospace" />
-    </ScrollView>
-</LinearLayout>

usbSerialExamples/src/main/res/menu/menu_devices.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:id="@+id/refresh"
+        android:title="Refresh devices" />
+    <item
+        android:id="@+id/baud_rate"
+        android:title="Baud rate" />
+    <item
+        android:id="@+id/read_mode"
+        android:title="Read mode" />
+</menu>

usbSerialExamples/src/main/res/menu/menu_terminal.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:id="@+id/clear"
+        android:icon="@drawable/ic_delete_white_24dp"
+        android:title="Clear"
+        app:showAsAction="always" />
+    <item
+        android:id="@+id/send_break"
+        android:title="Send BREAK"
+        app:showAsAction="never" />
+</menu>

usbSerialExamples/src/main/res/values/arrays.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string-array name="baud_rates">
+        <item>2400</item>
+        <item>9600</item>
+        <item>19200</item>
+        <item>57600</item>
+        <item>115200</item>
+    </string-array>
+    <string-array name="read_modes">
+        <item>event: SerialInputOutputManager.onNewData()</item>
+        <item>direct: UsbSerialPort.read()</item>
+    </string-array>
+</resources>

usbSerialExamples/src/main/res/values/colors.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="colorPrimary">#949C29</color>
+    <color name="colorPrimaryDark">#61671B</color>
+    <color name="colorAccent">#D8E33B</color>
+
+    <color name="colorRecieveText">#00FF00</color>
+    <color name="colorSendText">#82CAFF</color>
+    <color name="colorStatusText">#FFDB58</color>
+</resources>

usbSerialExamples/src/main/res/values/strings.xml

@@ -1,10 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-
-    <string name="app_title">USB Serial Example</string>
-    <string name="app_name">Serial Example</string>
-    <string name="refreshing">Refreshing...</string>
-    <string name="textBtnRTS">RTS - Request To Send</string>
-    <string name="textBtnDTR">DTR - Data Terminal Ready</string>
-
+    <string name="app_title">USB Serial For Android Example</string>
+    <string name="app_name">USB Serial Example</string>
+    <string name="devices">USB Devices</string>
 </resources>

usbSerialExamples/src/main/res/values/styles.xml

@@ -0,0 +1,7 @@
+<resources>
+    <style name="AppTheme" parent="Theme.AppCompat.NoActionBar">
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+</resources>

usbSerialExamples/src/main/res/xml/device_filter.xml

@@ -1,23 +1,38 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <!-- 0x0403 / 0x6001: FTDI FT232R UART -->
-    <usb-device vendor-id="1027" product-id="24577" />
-    
-    <!-- 0x0403 / 0x6015: FTDI FT231X -->
-    <usb-device vendor-id="1027" product-id="24597" />
+    <!-- 0x0403 / 0x60??: FTDI -->
+    <usb-device vendor-id="1027" product-id="24577" /> <!-- 0x6001: FT232R -->
+    <usb-device vendor-id="1027" product-id="24592" /> <!-- 0x6010: FT2232H -->
+    <usb-device vendor-id="1027" product-id="24593" /> <!-- 0x6011: FT4232H -->
+    <usb-device vendor-id="1027" product-id="24596" /> <!-- 0x6014: FT232H -->
+    <usb-device vendor-id="1027" product-id="24597" /> <!-- 0x6015: FT230X, FT231X, FT234XD -->
 
-    <!-- 0x2341 / Arduino -->
-    <usb-device vendor-id="9025" />
+    <!-- 0x10C4 / 0xEA??: Silabs CP210x -->
+    <usb-device vendor-id="4292" product-id="60000" /> <!-- 0xea60: CP2102 and other CP210x single port devices -->
+    <usb-device vendor-id="4292" product-id="60016" /> <!-- 0xea70: CP2105 -->
+    <usb-device vendor-id="4292" product-id="60017" /> <!-- 0xea71: CP2108 -->
 
-    <!-- 0x16C0 / 0x0483: Teensyduino  -->
-    <usb-device vendor-id="5824" product-id="1155" />
+    <!-- 0x067B / 0x23?3: Prolific PL2303x -->
+    <usb-device vendor-id="1659" product-id="8963" /> <!-- 0x2303: PL2303HX, HXD, TA, ... -->
+    <usb-device vendor-id="1659" product-id="9123" /> <!-- 0x23a3: PL2303GC -->
+    <usb-device vendor-id="1659" product-id="9139" /> <!-- 0x23b3: PL2303GB -->
+    <usb-device vendor-id="1659" product-id="9155" /> <!-- 0x23c3: PL2303GT -->
+    <usb-device vendor-id="1659" product-id="9171" /> <!-- 0x23d3: PL2303GL -->
+    <usb-device vendor-id="1659" product-id="9187" /> <!-- 0x23e3: PL2303GE -->
+    <usb-device vendor-id="1659" product-id="9203" /> <!-- 0x23f3: PL2303GS -->
 
-    <!-- 0x10C4 / 0xEA60: CP210x UART Bridge -->
-    <usb-device vendor-id="4292" product-id="60000" />
-    
-    <!-- 0x067B / 0x2303: Prolific PL2303 -->
-    <usb-device vendor-id="1659" product-id="8963" />
-    
-    <!-- 0x1a86 / 0x7523: Qinheng CH340 -->
-    <usb-device vendor-id="6790" product-id="29987" />
+    <!-- 0x1a86 / 0x?523: Qinheng CH34x -->
+    <usb-device vendor-id="6790" product-id="21795" /> <!-- 0x5523: CH341A -->
+    <usb-device vendor-id="6790" product-id="29987" /> <!-- 0x7523: CH340 -->
+
+    <!-- CDC driver -->
+    <usb-device vendor-id="9025" />                   <!-- 0x2341 / ......: Arduino -->
+    <usb-device vendor-id="5824" product-id="1155" /> <!-- 0x16C0 / 0x0483: Teensyduino  -->
+    <usb-device vendor-id="1003" product-id="8260" /> <!-- 0x03EB / 0x2044: Atmel Lufa -->
+    <usb-device vendor-id="7855" product-id="4"    /> <!-- 0x1eaf / 0x0004: Leaflabs Maple -->
+    <usb-device vendor-id="3368" product-id="516"  /> <!-- 0x0d28 / 0x0204: ARM mbed -->
+    <usb-device vendor-id="1155" product-id="22336" /><!-- 0x0483 / 0x5740: ST CDC -->
+    <usb-device vendor-id="11914" product-id="5"   /> <!-- 0x2E8A / 0x0005: Raspberry Pi Pico Micropython -->
+    <usb-device vendor-id="11914" product-id="10"  /> <!-- 0x2E8A / 0x000A: Raspberry Pi Pico SDK -->
+    <usb-device vendor-id="6790" product-id="21972" /><!-- 0x1A86 / 0x55D4: Qinheng CH9102F -->
 </resources>

usbSerialForAndroid/build.gradle

@@ -1,32 +1,60 @@
-apply plugin: 'com.android.library'
+plugins {
+    id 'com.android.library'
+    id 'maven-publish'
+}
 
 android {
-    compileSdkVersion 28
-    buildToolsVersion '28.0.3'
+    compileSdkVersion 35
 
     defaultConfig {
         minSdkVersion 17
-        targetSdkVersion 28
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        targetSdkVersion 35
+        consumerProguardFiles 'proguard-rules.pro'
+        
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunnerArguments = [                    // Raspi   Windows   LinuxVM   ...
+                'rfc2217_server_host': '192.168.0.78',
+                'rfc2217_server_nonstandard_baudrates': 'true',   // true    false     false
+        ]
     }
-
-    buildTypes {
-        release {
-            minifyEnabled false
-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    namespace 'com.hoho.android.usbserial'
+    publishing {
+        // if coverage is enabled, change 'release' to 'anyDeviceRelease' or comment out publishing rule
+        singleVariant('release') {
+            withSourcesJar()
         }
     }
 }
 
 dependencies {
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'com.android.support:support-annotations:28.0.0'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'commons-net:commons-net:3.6'
-    androidTestImplementation 'org.apache.commons:commons-lang3:3.8.1'
+    implementation "androidx.annotation:annotation:1.9.1"
+    testImplementation 'junit:junit:4.13.2'
+    testImplementation 'org.mockito:mockito-core:5.15.2'
+    androidTestImplementation 'androidx.appcompat:appcompat:1.6.1' // later versions have minsdk 21
+    androidTestImplementation 'androidx.test:core:1.5.0' // later versions have minsdk 19
+    androidTestImplementation 'androidx.test:runner:1.5.2' // later versions have minsdk 19
+    androidTestImplementation 'commons-net:commons-net:3.9.0' // later versions fail on old Android devices with missing java.time.Duration class
+    androidTestImplementation 'org.apache.commons:commons-lang3:3.14.0'
 }
 
-// to build a .jar file use gradle task 'createFullJarRelease'
+// gradle task: publishToMavenLocal
+project.afterEvaluate {
+    publishing {
+        publications {
+            release(MavenPublication) {
+                from components.release
 
-// to deploy into local maven repository use gradle task 'publishToMavenLocal' and enable:
-//apply from: 'publishToMavenLocal.gradle'
+                // values used for local maven repo, jitpack uses github release:
+                groupId 'com.github.mik3y'
+                artifactId 'usb-serial-for-android'
+                version '3.8.0beta'
+            }
+        }
+    }
+}
+
+//apply from: 'coverage.gradle'

usbSerialForAndroid/coverage.gradle

@@ -0,0 +1,78 @@
+// see https://github.com/mik3y/usb-serial-for-android/wiki/Device-Tests-&-Coverage-Report for instructions
+apply plugin: 'jacoco'
+
+android {
+    flavorDimensions += 'device'
+    productFlavors {
+        anyDevice {
+            // Used as fallback in usbSerialExample/build.gradle -> missingDimensionStrategy, but not for coverage report
+            dimension 'device'
+        }
+        mcp2221 {
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'CdcAcm']
+        }
+        ch340 {
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Ch34x']
+        }
+        cp2102 { // and cp2105 first port
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Cp21xx', 'test_device_port': '0']
+        }
+        cp2105 { // second port
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Cp21xx', 'test_device_port': '1']
+        }
+        ft232 { // and ft2232 first port
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Ftdi', 'test_device_port': '0']
+        }
+        ft2232 { // second port
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Ftdi', 'test_device_port': '1']
+        }
+        pl2303 {
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Prolific']
+        }
+        pl2303t {
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Prolific']
+        }
+        pl2303g {
+            dimension 'device'
+            testInstrumentationRunnerArguments = ['test_device_driver': 'Prolific']
+        }
+    }
+
+    buildTypes {
+        debug {
+            enableUnitTestCoverage true
+            enableAndroidTestCoverage true
+        }
+    }
+}
+
+// create report even if tests fail
+project.gradle.taskGraph.whenReady {
+    -> project.tasks.findAll { it.name =~ /connected.+AndroidTest/ }.each {
+        it.ignoreFailures = true
+    }
+}
+
+task jacocoTestReport(type: JacocoReport, dependsOn: ['compileAnyDeviceDebugSources'
+                                                  /*, 'testAnyDeviceDebugUnitTest' */
+                                                  /*, 'create<device>DebugCoverageReport' */]) {
+    def fileFilter = ['**/R.class', '**/R$*.class', '**/BuildConfig.*', '**/Manifest*.*', '**/*Test*.*', 'android/**/*.*']
+    def debugTree = fileTree(dir: "$project.buildDir/intermediates/javac/anyDeviceDebug", excludes: fileFilter)
+    def mainSrc = "$project.projectDir/src/main/java"
+
+    reports.xml.required = true
+    sourceDirectories.from files([mainSrc])
+    classDirectories.from files([debugTree])
+    executionData.from fileTree(dir: project.buildDir, includes: [
+            'outputs/unit_test_code_coverage/anyDeviceDebugUnitTest/testAnyDeviceDebugUnitTest.exec',
+            'outputs/code_coverage/*DebugAndroidTest/connected/*/coverage.ec'
+    ])
+}

usbSerialForAndroid/proguard-rules.pro

@@ -0,0 +1 @@
+-keep class com.hoho.android.usbserial.driver.* { *; }

usbSerialForAndroid/publishToMavenLocal.gradle

@@ -1,20 +0,0 @@
-apply plugin: 'maven-publish'
-
-publishing {
-    publications {
-        maven(MavenPublication) {
-            groupId 'com.github.mik3y'
-            artifactId 'usb-serial-for-android'
-            version '1.x.0'
-            afterEvaluate {
-                artifact androidSourcesJar
-                artifact bundleReleaseAar
-            }
-        }
-    }
-}
-
-task androidSourcesJar(type: Jar) {
-    classifier 'sources'
-    from android.sourceSets.main.java.srcDirs
-}

usbSerialForAndroid/src/androidTest/AndroidManifest.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-      package="com.hoho.android.usbserial"
       android:versionCode="1"
       android:versionName="1.0">
     <uses-permission android:name="android.permission.INTERNET"/>

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/CrossoverTest.java

@@ -0,0 +1,216 @@
+/*
+ * test multiple devices or multiple ports on same device
+ *
+ * TxD and RxD have to be cross connected
+ */
+package com.hoho.android.usbserial;
+
+import android.content.Context;
+import android.hardware.usb.UsbManager;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+import android.util.Log;
+
+import com.hoho.android.usbserial.driver.UsbSerialDriver;
+import com.hoho.android.usbserial.driver.UsbSerialPort;
+import com.hoho.android.usbserial.driver.UsbSerialProber;
+import com.hoho.android.usbserial.util.TestBuffer;
+import com.hoho.android.usbserial.util.UsbWrapper;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
+import org.junit.runner.RunWith;
+
+import java.io.IOException;
+import java.util.EnumSet;
+import java.util.List;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
+import static org.junit.Assume.assumeTrue;
+
+@RunWith(AndroidJUnit4.class)
+public class CrossoverTest {
+
+    private final static String  TAG = CrossoverTest.class.getSimpleName();
+
+    private Context context;
+    private UsbManager usbManager;
+    private UsbWrapper usb1, usb2;
+
+    @Rule
+    public TestRule watcher = new TestWatcher() {
+        protected void starting(Description description) {
+            Log.i(TAG, "===== starting test: " + description.getMethodName()+ " =====");
+        }
+    };
+
+    @Before
+    public void setUp() throws Exception {
+        assumeTrue("ignore test for device specific coverage report",
+                InstrumentationRegistry.getArguments().getString("test_device_driver") == null);
+
+        context = ApplicationProvider.getApplicationContext();
+        usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
+        List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(usbManager);
+        assertNotEquals("no USB device found", 0, availableDrivers.size());
+        if (availableDrivers.size() == 0) {
+            fail("no USB device found");
+        } else if (availableDrivers.size() == 1) {
+            assertEquals("expected device with 2 ports.", 2, availableDrivers.get(0).getPorts().size());
+            usb1 = new UsbWrapper(context, availableDrivers.get(0), 0);
+            usb2 = new UsbWrapper(context, availableDrivers.get(0), 1);
+        } else {
+            assertEquals("expected 2 devices with 1 port.", 1, availableDrivers.get(0).getPorts().size());
+            assertEquals("expected 2 devices with 1 port.", 1, availableDrivers.get(1).getPorts().size());
+            usb1 = new UsbWrapper(context, availableDrivers.get(0), 0);
+            usb2 = new UsbWrapper(context, availableDrivers.get(1), 0);
+        }
+        usb1.setUp();
+        usb2.setUp();
+    }
+
+    @Test
+    public void reopen() throws Exception {
+        byte[] buf;
+
+        usb1.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        usb2.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        usb1.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb2.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+
+        usb1.write("x".getBytes());
+        buf = usb2.read(1);
+        assertThat(buf, equalTo("x".getBytes()));
+
+        usb2.write("y".getBytes());
+        buf = usb1.read(1);
+        assertThat(buf, equalTo("y".getBytes()));
+
+        usb2.close(); // does not affect usb1 with individual UsbDeviceConnection on same device
+
+        usb2.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        usb2.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+
+        usb1.write("x".getBytes());
+        buf = usb2.read(1);
+        assertThat(buf, equalTo("x".getBytes()));
+
+        usb2.write("y".getBytes());
+        buf = usb1.read(1);
+        assertThat(buf, equalTo("y".getBytes()));
+
+        usb1.close();
+        usb2.close();
+    }
+
+    @Test
+    public void ioManager() throws Exception {
+        byte[] buf;
+
+        // each SerialInputOutputManager thread runs in it's own SingleThreadExecutor
+        usb1.open();
+        usb2.open();
+        usb1.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb2.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+
+        usb1.write("x".getBytes());
+        buf = usb2.read(1);
+        assertThat(buf, equalTo("x".getBytes()));
+
+        usb2.write("y".getBytes());
+        buf = usb1.read(1);
+        assertThat(buf, equalTo("y".getBytes()));
+
+        usb1.close();
+        usb2.close();
+    }
+
+    @Test
+    public void baudRate() throws Exception {
+        byte[] buf;
+
+        usb1.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        usb2.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        usb1.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb2.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
+
+        // a - start bit (0)
+        // o - stop bit  (1)
+        // 0/1 - data bit
+
+        // out 19k2: a00011001o
+        // in 9k6:   a 0 1 0 1 1 1 1 1 o
+        usb1.write(new byte[]{(byte)0x98});
+        buf = usb2.read(1);
+        assertThat(buf, equalTo(new byte[]{(byte)0xfa}));
+
+        // out 9k6: a 1 0 1 1 1 1 1 1 o
+        // in 19k2: a01100111o
+        usb2.write(new byte[]{(byte)0xfd});
+        buf = usb1.read(1);
+        assertThat(buf, equalTo(new byte[]{(byte)0xe6}));
+
+        usb1.close();
+        usb2.close();
+    }
+
+    @Test
+    public void concurrent() throws Exception {
+        // 115200 baud ~= 11kB/sec => ~1.5 second test duration with 16kB tbuf
+        // concurrent (+ blocking) write calls as tbuf larger than any buffer size returned by UsbWrapper.getWriteSizes()
+        // concurrent read calls in IoManager threads
+        TestBuffer tbuf1 = new TestBuffer(16*1024);
+        TestBuffer tbuf2 = new TestBuffer(16*1024);
+
+        class WriteRunnable implements Runnable {
+            public WriteRunnable(int port) { this.port = port; }
+            private final int port;
+            Exception exc;
+            @Override
+            public void run() {
+                byte[] buf = new byte[1024];
+                try {
+                    for(int i=0; i<tbuf1.buf.length / 1024; i++) {
+                        System.arraycopy(tbuf1.buf, i*1024, buf, 0, 1024);
+                        if (port == 1)
+                            usb1.write(buf);
+                        else
+                            usb2.write(buf);
+                    }
+                } catch (IOException exc) {
+                    this.exc = exc;
+                }
+            }
+        }
+
+        usb1.open();
+        usb2.open();
+        usb1.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb2.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
+        WriteRunnable wr1 = new WriteRunnable(1), wr2 = new WriteRunnable(2);
+        Thread wt1 = new Thread(wr1), wt2 = new Thread(wr2);
+        boolean done1 = false, done2 = false;
+        wt1.start();
+        Thread.sleep(50);
+        wt2.start();
+        while(!done1 && !done2) {
+            if(!done1)
+                done1 = tbuf1.testRead(usb1.read(-1));
+            if(!done2)
+                done2 = tbuf2.testRead(usb2.read(-1));
+        }
+        wt1.join(); wt2.join();
+        assertNull(wr1.exc);
+        assertNull(wr2.exc);
+    }
+}

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/CommonUsbSerialPortWrapper.java

@@ -0,0 +1,8 @@
+package com.hoho.android.usbserial.driver;
+
+public class CommonUsbSerialPortWrapper {
+    public static byte[] getWriteBuffer(UsbSerialPort serialPort) {
+        CommonUsbSerialPort commonSerialPort = (CommonUsbSerialPort) serialPort;
+        return commonSerialPort.mWriteBuffer;
+    }
+}

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/ProlificSerialPortWrapper.java

@@ -0,0 +1,13 @@
+package com.hoho.android.usbserial.driver;
+
+public class ProlificSerialPortWrapper {
+    public static boolean isDeviceTypeT(UsbSerialPort serialPort) {
+        ProlificSerialDriver.ProlificSerialPort prolificSerialPort = (ProlificSerialDriver.ProlificSerialPort) serialPort;
+        return prolificSerialPort.mDeviceType == ProlificSerialDriver.DeviceType.DEVICE_TYPE_T;
+    }
+
+    public static boolean isDeviceTypeHxn(UsbSerialPort serialPort) {
+        ProlificSerialDriver.ProlificSerialPort prolificSerialPort = (ProlificSerialDriver.ProlificSerialPort) serialPort;
+        return prolificSerialPort.mDeviceType == ProlificSerialDriver.DeviceType.DEVICE_TYPE_HXN;
+    }
+}

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/TelnetWrapper.java

@@ -0,0 +1,152 @@
+package com.hoho.android.usbserial.util;
+
+import com.hoho.android.usbserial.driver.UsbSerialPort;
+
+import org.apache.commons.net.telnet.InvalidTelnetOptionException;
+import org.apache.commons.net.telnet.TelnetClient;
+import org.apache.commons.net.telnet.TelnetCommand;
+import org.apache.commons.net.telnet.TelnetOptionHandler;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+
+import static org.junit.Assert.assertEquals;
+
+public class TelnetWrapper {
+    private final static String  TAG = TelnetWrapper.class.getSimpleName();
+
+    private final static int     TELNET_READ_WAIT = 500;
+    private final static int     TELNET_COMMAND_WAIT = 2000;
+
+    private final static byte    RFC2217_COM_PORT_OPTION = 0x2c;
+    private final static byte    RFC2217_SET_BAUDRATE = 1;
+    private final static byte    RFC2217_SET_DATASIZE = 2;
+    private final static byte    RFC2217_SET_PARITY   = 3;
+    private final static byte    RFC2217_SET_STOPSIZE = 4;
+    private final static byte    RFC2217_PURGE_DATA = 12;
+
+    private final String host;
+    private final int port;
+
+    private TelnetClient telnetClient;
+    private InputStream readStream;
+    private OutputStream writeStream;
+    private ArrayList<int[]> commandResponse = new ArrayList<>();
+    public int writeDelay = 0;
+
+    public TelnetWrapper(String host, int port) {
+        this.host = host;
+        this.port = port;
+        telnetClient = null;
+    }
+
+    private void setUpFixtureInt() throws Exception {
+        if(telnetClient != null)
+            return;
+        telnetClient = new TelnetClient();
+        telnetClient.addOptionHandler(new TelnetOptionHandler(RFC2217_COM_PORT_OPTION, false, false, false, false) {
+            @Override
+            public int[] answerSubnegotiation(int[] suboptionData, int suboptionLength) {
+                int[] data = new int[suboptionLength];
+                System.arraycopy(suboptionData, 0, data, 0, suboptionLength);
+                commandResponse.add(data);
+                return super.answerSubnegotiation(suboptionData, suboptionLength);
+            }
+        });
+
+        telnetClient.setConnectTimeout(2000);
+        telnetClient.connect(host, port);
+        telnetClient.setTcpNoDelay(true);
+        writeStream = telnetClient.getOutputStream();
+        readStream = telnetClient.getInputStream();
+    }
+
+    private int[] doCommand(String name, byte[] command) throws IOException, InterruptedException {
+        commandResponse.clear();
+        telnetClient.sendCommand((byte) TelnetCommand.SB);
+        writeStream.write(command);
+        telnetClient.sendCommand((byte)TelnetCommand.SE);
+
+        for(int i=0; i<TELNET_COMMAND_WAIT; i++) {
+            if(commandResponse.size() > 0) break;
+            Thread.sleep(1);
+        }
+        assertEquals("RFC2217 " + name+ " w/o response.", 1, commandResponse.size());
+        //Log.d(TAG, name + " -> " + Arrays.toString(commandResponse.get(0)));
+        return commandResponse.get(0);
+    }
+
+    public void setUp() throws Exception {
+        setUpFixtureInt();
+        telnetClient.sendAYT(1000); // not correctly handled by rfc2217_server.py, but WARNING output "ignoring Telnet command: '\xf6'" is a nice separator between tests
+        doCommand("purge-data", new byte[] {RFC2217_COM_PORT_OPTION, RFC2217_PURGE_DATA, 3});
+        writeDelay = 0;
+    }
+
+    public void tearDown() {
+        try {
+            read(0);
+        } catch (Exception ignored) {
+        }
+    }
+
+    public void tearDownFixture() throws Exception {
+        try {
+            telnetClient.disconnect();
+        } catch (Exception ignored) {}
+        readStream = null;
+        writeStream = null;
+        telnetClient = null;
+    }
+
+    // wait full time
+    public byte[] read() throws Exception {
+        return read(-1, -1);
+    }
+    public byte[] read(int expectedLength) throws Exception {
+        return read(expectedLength, -1);
+    }
+    public byte[] read(int expectedLength, int readWait) throws Exception {
+        if(readWait == -1)
+            readWait = TELNET_READ_WAIT;
+        long end = System.currentTimeMillis() + readWait;
+        ByteBuffer buf = ByteBuffer.allocate(65536);
+        while(System.currentTimeMillis() < end) {
+            if(readStream.available() > 0) {
+                buf.put((byte) readStream.read());
+            } else {
+                if (expectedLength >= 0 && buf.position() >= expectedLength)
+                    break;
+                Thread.sleep(1);
+            }
+        }
+        byte[] data = new byte[buf.position()];
+        buf.flip();
+        buf.get(data);
+        return data;
+    }
+
+    public void write(byte[] data) throws Exception{
+        if(writeDelay != 0) {
+            for(byte b : data) {
+                writeStream.write(b);
+                writeStream.flush();
+                Thread.sleep(writeDelay);
+            }
+        } else {
+            writeStream.write(data);
+            writeStream.flush();
+        }
+    }
+
+    public void setParameters(int baudRate, int dataBits, int stopBits, @UsbSerialPort.Parity int parity) throws IOException, InterruptedException, InvalidTelnetOptionException {
+        doCommand("set-baudrate", new byte[] {RFC2217_COM_PORT_OPTION, RFC2217_SET_BAUDRATE, (byte)(baudRate>>24), (byte)(baudRate>>16), (byte)(baudRate>>8), (byte)baudRate});
+        doCommand("set-datasize", new byte[] {RFC2217_COM_PORT_OPTION, RFC2217_SET_DATASIZE, (byte)dataBits});
+        doCommand("set-stopsize", new byte[] {RFC2217_COM_PORT_OPTION, RFC2217_SET_STOPSIZE, (byte)stopBits});
+        doCommand("set-parity", new byte[] {RFC2217_COM_PORT_OPTION, RFC2217_SET_PARITY, (byte)(parity+1)});
+    }
+
+}

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/TestBuffer.java

@@ -0,0 +1,32 @@
+package com.hoho.android.usbserial.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+public class TestBuffer {
+    public final byte[] buf;
+    public int len;
+
+    public TestBuffer(int length) {
+        len = 0;
+        buf = new byte[length];
+        int i = 0;
+        int j = 0;
+        for (j = 0; j < length / 16; j++)
+            for (int k = 0; k < 16; k++)
+                buf[i++] = (byte) j;
+        while (i < length)
+            buf[i++] = (byte) j;
+    }
+
+    public boolean testRead(byte[] data) {
+        assertNotEquals(0, data.length);
+        assertTrue("got " + (len + data.length) + " bytes", (len + data.length) <= buf.length);
+        for (int j = 0; j < data.length; j++)
+            assertEquals("at pos " + (len + j), (byte) ((len + j) / 16), data[j]);
+        len += data.length;
+        //Log.d(TAG, "read " + len);
+        return len == buf.length;
+    }
+}

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/UsbWrapper.java

@@ -0,0 +1,390 @@
+package com.hoho.android.usbserial.util;
+
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbManager;
+import android.media.RingtoneManager;
+import android.net.Uri;
+import android.os.Build;
+import android.util.Log;
+
+import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
+import com.hoho.android.usbserial.driver.Ch34xSerialDriver;
+import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
+import com.hoho.android.usbserial.driver.Cp21xxSerialDriver;
+import com.hoho.android.usbserial.driver.FtdiSerialDriver;
+import com.hoho.android.usbserial.driver.ProlificSerialDriver;
+import com.hoho.android.usbserial.driver.ProlificSerialPortWrapper;
+import com.hoho.android.usbserial.driver.UsbId;
+import com.hoho.android.usbserial.driver.UsbSerialDriver;
+import com.hoho.android.usbserial.driver.UsbSerialPort;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Deque;
+import java.util.EnumSet;
+import java.util.LinkedList;
+import java.util.concurrent.Callable;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import androidx.core.content.ContextCompat;
+
+public class UsbWrapper implements SerialInputOutputManager.Listener {
+
+    public final static int     USB_READ_WAIT = 500;
+    public final static int     USB_WRITE_WAIT = 500;
+    private static final String TAG = UsbWrapper.class.getSimpleName();
+
+    public enum OpenCloseFlags { NO_IOMANAGER_THREAD, NO_IOMANAGER_START, NO_CONTROL_LINE_INIT, NO_DEVICE_CONNECTION };
+
+    // constructor
+    final Context context;
+    public final UsbSerialDriver serialDriver;
+    public final int devicePort;
+    public final UsbSerialPort serialPort;
+    // open
+    public UsbDeviceConnection deviceConnection;
+    public SerialInputOutputManager ioManager;
+    // read
+    final Deque<byte[]> readBuffer = new LinkedList<>();
+    Exception readError;
+    public boolean readBlock = false;
+    long readTime = 0;
+
+    // device properties
+    public boolean isCp21xxRestrictedPort; // second port of Cp2105 has limited dataBits, stopBits, parity
+    public boolean outputLinesSupported;
+    public boolean inputLinesSupported;
+    public boolean inputLinesConnected;
+    public boolean inputLinesOnlyRtsCts;
+    public int writePacketSize = -1;
+    public int writeBufferSize = -1;
+    public int readBufferSize = -1;
+
+    public UsbWrapper(Context context, UsbSerialDriver serialDriver, int devicePort) {
+        this.context = context;
+        this.serialDriver = serialDriver;
+        this.devicePort = devicePort;
+        serialPort = serialDriver.getPorts().get(devicePort);
+        CommonUsbSerialPort.DEBUG = true;
+    }
+
+    public void setUp() throws Exception {
+        UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
+        if (!usbManager.hasPermission(serialDriver.getDevice())) {
+            Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
+            RingtoneManager.getRingtone(context, notification).play();
+
+            Log.d(TAG,"USB permission ...");
+            final Boolean[] granted = {null};
+            BroadcastReceiver usbReceiver = new BroadcastReceiver() {
+                @Override
+                public void onReceive(Context context, Intent intent) {
+                    granted[0] = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false);
+                }
+            };
+            int flags = Build.VERSION.SDK_INT >= Build.VERSION_CODES.M ? PendingIntent.FLAG_MUTABLE : 0;
+            Intent intent = new Intent("com.android.example.USB_PERMISSION");
+            intent.setPackage(context.getPackageName());
+            PendingIntent permissionIntent = PendingIntent.getBroadcast(context, 0, intent, flags);
+            IntentFilter filter = new IntentFilter("com.android.example.USB_PERMISSION");
+            ContextCompat.registerReceiver(context, usbReceiver, filter, Context.RECEIVER_NOT_EXPORTED);
+            usbManager.requestPermission(serialDriver.getDevice(), permissionIntent);
+            for(int i=0; i<5000; i++) {
+                if(granted[0] != null) break;
+                Thread.sleep(1);
+            }
+            Log.d(TAG,"USB permission "+granted[0]);
+            assertTrue("USB permission dialog not confirmed", granted[0] != null && granted[0]);
+        }
+
+        // extract some device properties:
+        isCp21xxRestrictedPort = serialDriver instanceof Cp21xxSerialDriver && serialDriver.getPorts().size()==2 && serialPort.getPortNumber() == 1;
+        // output lines are supported by all common drivers
+        // input lines are supported by all common drivers except CDC
+        if (serialDriver instanceof FtdiSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getDevice().getProductId() == UsbId.FTDI_FT2232H)
+                inputLinesConnected = true; // I only have 74LS138 connected at FT2232, not at FT232
+            if(serialDriver.getDevice().getProductId() == UsbId.FTDI_FT231X) {
+                inputLinesConnected = true;
+                inputLinesOnlyRtsCts = true; // I only test with FT230X that has only these 2 control lines. DTR is silently ignored
+            }
+        } else if (serialDriver instanceof Cp21xxSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getPorts().size() == 1)
+                inputLinesConnected = true; // I only have 74LS138 connected at CP2102, not at CP2105
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            inputLinesConnected = true;
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getDevice().getProductId() == UsbId.QINHENG_CH340)
+                inputLinesConnected = true;  // I only have 74LS138 connected at CH340, not connected at CH341A
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            outputLinesSupported = true;
+        }
+
+        if (serialDriver instanceof Cp21xxSerialDriver) {
+            if (serialDriver.getPorts().size() == 1) { writePacketSize = 64; writeBufferSize = 576; }
+            else if (serialPort.getPortNumber() == 0) { writePacketSize = 64; writeBufferSize = 320; }
+            else { writePacketSize = 32; writeBufferSize = 128; }; //, 160}; // write buffer size detection is unreliable
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            writePacketSize = 32; writeBufferSize = 64;
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            writePacketSize = 64; writeBufferSize = 256;
+        } else if (serialDriver instanceof FtdiSerialDriver) {
+            switch (serialDriver.getPorts().size()) {
+                case 1: writePacketSize = 64; writeBufferSize = 128; break;
+                case 2: writePacketSize = 512; writeBufferSize = 4096; break;
+                case 4: writePacketSize = 512; writeBufferSize = 2048; break;
+            }
+            if(serialDriver.getDevice().getProductId() == UsbId.FTDI_FT231X)
+                writeBufferSize = 512;
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            writePacketSize = 16; writeBufferSize = 32; // MCP2221 values, other devices might be different
+        }
+
+        readBufferSize = writeBufferSize;
+        if (serialDriver instanceof Cp21xxSerialDriver && serialDriver.getPorts().size() == 2) {
+            readBufferSize = 256;
+        } else if (serialDriver instanceof FtdiSerialDriver && serialDriver.getPorts().size() == 1 && serialDriver.getDevice().getProductId() != UsbId.FTDI_FT231X) {
+            readBufferSize = 256;
+        } // PL2303 HXN checked in open()
+    }
+
+    public void tearDown() {
+        try {
+            if (ioManager != null)
+                read(0);
+            else
+                serialPort.purgeHwBuffers(true, true);
+        } catch (Exception ignored) {
+        }
+        close();
+        //usb.serialDriver = null;
+    }
+
+    public void close() {
+        close(EnumSet.noneOf(OpenCloseFlags.class));
+    }
+
+    public void close(EnumSet<OpenCloseFlags> flags) {
+        if (ioManager != null) {
+            ioManager.setListener(null);
+            ioManager.stop();
+        }
+        if (serialPort != null) {
+            try {
+                if(!flags.contains(OpenCloseFlags.NO_CONTROL_LINE_INIT)) {
+                    serialPort.setDTR(false);
+                    serialPort.setRTS(false);
+                    if (serialPort.getFlowControl() != UsbSerialPort.FlowControl.NONE)
+                        serialPort.setFlowControl(UsbSerialPort.FlowControl.NONE);
+                }
+            } catch (Exception ignored) {
+            }
+            try {
+                serialPort.close();
+            } catch (Exception ignored) {
+            }
+            //usbSerialPort = null;
+        }
+        if(!flags.contains(OpenCloseFlags.NO_DEVICE_CONNECTION)) {
+            deviceConnection = null; // closed in usbSerialPort.close()
+        }
+        if(ioManager != null) {
+            for (int i = 0; i < 2000; i++) {
+                if (SerialInputOutputManager.State.STOPPED == ioManager.getState()) break;
+                try {
+                    Thread.sleep(1);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+            assertEquals(SerialInputOutputManager.State.STOPPED, ioManager.getState());
+            ioManager = null;
+        }
+    }
+
+    public void open() throws Exception {
+        open(EnumSet.noneOf(OpenCloseFlags.class));
+    }
+
+    public void open(EnumSet<OpenCloseFlags> flags) throws Exception {
+        if(!flags.contains(OpenCloseFlags.NO_DEVICE_CONNECTION)) {
+            UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
+            deviceConnection = usbManager.openDevice(serialDriver.getDevice());
+        }
+        serialPort.open(deviceConnection);
+        if(!flags.contains(OpenCloseFlags.NO_CONTROL_LINE_INIT)) {
+            serialPort.setDTR(true);
+            serialPort.setRTS(true);
+        }
+        if(!flags.contains(OpenCloseFlags.NO_IOMANAGER_THREAD)) {
+            ioManager = new SerialInputOutputManager(serialPort, this);
+            if(!flags.contains(OpenCloseFlags.NO_IOMANAGER_START))
+                ioManager.start();
+        }
+        synchronized (readBuffer) {
+            readBuffer.clear();
+        }
+        readError = null;
+
+        if (serialDriver instanceof ProlificSerialDriver && ProlificSerialPortWrapper.isDeviceTypeHxn(serialPort)) {
+            readBufferSize = 768;
+        }
+    }
+
+    public void waitForIoManagerStarted() throws IOException {
+        for (int i = 0; i < 100; i++) {
+            if (SerialInputOutputManager.State.STOPPED != ioManager.getState()) return;
+            try {
+                Thread.sleep(1);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+        throw new IOException("IoManager not started");
+    }
+
+    public boolean hasIoManagerThreads() {
+        int c = 0;
+        for (Thread thread : Thread.getAllStackTraces().keySet()) {
+            if (thread.getName().equals(SerialInputOutputManager.class.getSimpleName() + "_read"))
+                c += 1;
+            if (thread.getName().equals(SerialInputOutputManager.class.getSimpleName() + "_write"))
+                c += 1;
+        }
+        return c == 2;
+    }
+
+    // wait full time
+    public byte[] read() throws Exception {
+        return read(-1, -1, -1);
+    }
+    public byte[] read(int expectedLength) throws Exception {
+        return read(expectedLength, -1, -1);
+    }
+    public byte[] read(int expectedLength, int readBufferSize) throws Exception {
+        return read(expectedLength, readBufferSize, -1);
+    }
+    public byte[] read(int expectedLength, int readBufferSize, int readWait) throws Exception {
+        if(readWait == -1)
+            readWait = USB_READ_WAIT;
+        long end = System.currentTimeMillis() + readWait;
+        ByteBuffer buf = ByteBuffer.allocate(16*1024);
+        if(ioManager != null) {
+            while (System.currentTimeMillis() < end) {
+                if(readError != null)
+                    throw new IOException(readError);
+                synchronized (readBuffer) {
+                    while(readBuffer.peek() != null)
+                        buf.put(readBuffer.remove());
+                }
+                if (expectedLength >= 0 && buf.position() >= expectedLength)
+                    break;
+                Thread.sleep(1);
+            }
+
+        } else {
+            byte[] b1 = new byte[readBufferSize > 0 ? readBufferSize : 256];
+            while (System.currentTimeMillis() < end) {
+                int len = serialPort.read(b1, USB_READ_WAIT);
+                if (len > 0)
+                    buf.put(b1, 0, len);
+                if (expectedLength >= 0 && buf.position() >= expectedLength)
+                    break;
+            }
+        }
+        byte[] data = new byte[buf.position()];
+        buf.flip();
+        buf.get(data);
+        return data;
+    }
+
+    public void write(byte[] data) throws IOException {
+        serialPort.write(data, USB_WRITE_WAIT);
+    }
+
+    public void setParameters(int baudRate, int dataBits, int stopBits, @UsbSerialPort.Parity int parity) throws IOException, InterruptedException {
+        serialPort.setParameters(baudRate, dataBits, stopBits, parity);
+        if(serialDriver instanceof CdcAcmSerialDriver)
+            Thread.sleep(10); // arduino_leonardeo_bridge.ini needs some time
+        else
+            Thread.sleep(1);
+    }
+
+    /* return TRUE/FALSE/null instead of true/false/<throw UnsupportedOperationException> */
+    public Boolean getControlLine(Callable<?> callable) throws Exception {
+        try {
+            return (Boolean)callable.call();
+        } catch (UnsupportedOperationException t) {
+            return null;
+        }
+    }
+
+    // return [write packet size, write buffer size(s)]
+    public int[] getWriteSizes() {
+        if (serialDriver instanceof Cp21xxSerialDriver) {
+            if (serialDriver.getPorts().size() == 1) return new int[]{64, 576};
+            else if (serialPort.getPortNumber() == 0) return new int[]{64, 320};
+            else return new int[]{32, 128, 160}; // write buffer size detection is unreliable
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            return new int[]{32, 64};
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            return new int[]{64, 256};
+        } else if (serialDriver instanceof FtdiSerialDriver) {
+            switch (serialDriver.getPorts().size()) {
+                case 1: return new int[]{64, 128};
+                case 2: return new int[]{512, 4096};
+                case 4: return new int[]{512, 2048};
+                default: return null;
+            }
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            return new int[]{64, 128};
+        } else {
+            return null;
+        }
+    }
+
+
+    @Override
+    public void onNewData(byte[] data) {
+        long now = System.currentTimeMillis();
+        if(readTime == 0)
+            readTime = now;
+        if(data.length > 64) {
+            Log.d(TAG, "usb " + devicePort + " read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data, 0, 32) + "..." + new String(data, data.length-32, 32));
+        } else {
+            Log.d(TAG, "usb " + devicePort + " read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data));
+        }
+        readTime = now;
+
+        while(readBlock)
+            try {
+                Thread.sleep(1);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        synchronized (readBuffer) {
+            readBuffer.add(data);
+        }
+    }
+
+    @Override
+    public void onRunError(Exception e) {
+        readError = e;
+    }
+
+}

usbSerialForAndroid/src/main/AndroidManifest.xml

@@ -1,4 +1,3 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-      package="com.hoho.android.usbserial">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
 </manifest>

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriver.java

@@ -1,436 +1,359 @@
-/* Copyright 2011-2013 Google Inc.
- * Copyright 2013 mike wakerly <opensource@hoho.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
- * Project home page: https://github.com/mik3y/usb-serial-for-android
- */
-
-package com.hoho.android.usbserial.driver;
-
-import android.hardware.usb.UsbConstants;
-import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
-import android.hardware.usb.UsbEndpoint;
-import android.hardware.usb.UsbInterface;
-import android.hardware.usb.UsbRequest;
-import android.util.Log;
-
-import java.io.IOException;
-import java.nio.ByteBuffer;
-import java.util.Collections;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-
-/**
- * USB CDC/ACM serial driver implementation.
- *
- * @author mike wakerly (opensource@hoho.com)
- * @see <a
- *      href="http://www.usb.org/developers/devclass_docs/usbcdc11.pdf">Universal
- *      Serial Bus Class Definitions for Communication Devices, v1.1</a>
- */
-public class CdcAcmSerialDriver implements UsbSerialDriver {
-
-    private final String TAG = CdcAcmSerialDriver.class.getSimpleName();
-
-    private final UsbDevice mDevice;
-    private final UsbSerialPort mPort;
-
-    public CdcAcmSerialDriver(UsbDevice device) {
-        mDevice = device;
-        mPort = new CdcAcmSerialPort(device, 0);
-    }
-
-    @Override
-    public UsbDevice getDevice() {
-        return mDevice;
-    }
-
-    @Override
-    public List<UsbSerialPort> getPorts() {
-        return Collections.singletonList(mPort);
-    }
-
-    class CdcAcmSerialPort extends CommonUsbSerialPort {
-
-        private UsbInterface mControlInterface;
-        private UsbInterface mDataInterface;
-
-        private UsbEndpoint mControlEndpoint;
-        private UsbEndpoint mReadEndpoint;
-        private UsbEndpoint mWriteEndpoint;
-
-        private int mControlIndex;
-
-        private boolean mRts = false;
-        private boolean mDtr = false;
-
-        private static final int USB_RECIP_INTERFACE = 0x01;
-        private static final int USB_RT_ACM = UsbConstants.USB_TYPE_CLASS | USB_RECIP_INTERFACE;
-
-        private static final int SET_LINE_CODING = 0x20;  // USB CDC 1.1 section 6.2
-        private static final int GET_LINE_CODING = 0x21;
-        private static final int SET_CONTROL_LINE_STATE = 0x22;
-        private static final int SEND_BREAK = 0x23;
-
-        public CdcAcmSerialPort(UsbDevice device, int portNumber) {
-            super(device, portNumber);
-        }
-
-        @Override
-        public UsbSerialDriver getDriver() {
-            return CdcAcmSerialDriver.this;
-        }
-
-        @Override
-        public void open(UsbDeviceConnection connection) throws IOException {
-            if (mConnection != null) {
-                throw new IOException("Already open");
-            }
-
-            mConnection = connection;
-            boolean opened = false;
-            try {
-
-                if (1 == mDevice.getInterfaceCount()) {
-                    Log.d(TAG,"device might be castrated ACM device, trying single interface logic");
-                    openSingleInterface();
-                } else {
-                    Log.d(TAG,"trying default interface logic");
-                    openInterface();
-                }
-
-                opened = true;
-            } finally {
-                if (!opened) {
-                    mConnection = null;
-                    // just to be on the save side
-                    mControlEndpoint = null;
-                    mReadEndpoint = null;
-                    mWriteEndpoint = null;
-                }
-            }
-        }
-
-        private void openSingleInterface() throws IOException {
-            // the following code is inspired by the cdc-acm driver
-            // in the linux kernel
-
-            mControlIndex = 0;
-            mControlInterface = mDevice.getInterface(0);
-            Log.d(TAG, "Control iface=" + mControlInterface);
-
-            mDataInterface = mDevice.getInterface(0);
-            Log.d(TAG, "data iface=" + mDataInterface);
-
-            if (!mConnection.claimInterface(mControlInterface, true)) {
-                throw new IOException("Could not claim shared control/data interface.");
-            }
-
-            int endCount = mControlInterface.getEndpointCount();
-
-            if (endCount < 3) {
-                Log.d(TAG,"not enough endpoints - need 3. count=" + mControlInterface.getEndpointCount());
-                throw new IOException("Insufficient number of endpoints(" + mControlInterface.getEndpointCount() + ")");
-            }
-
-            // Analyse endpoints for their properties
-            mControlEndpoint = null;
-            mReadEndpoint = null;
-            mWriteEndpoint = null;
-            for (int i = 0; i < endCount; ++i) {
-                UsbEndpoint ep = mControlInterface.getEndpoint(i);
-                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) &&
-                    (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_INT)) {
-                    Log.d(TAG,"Found controlling endpoint");
-                    mControlEndpoint = ep;
-                } else if ((ep.getDirection() == UsbConstants.USB_DIR_IN) &&
-                           (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
-                    Log.d(TAG,"Found reading endpoint");
-                    mReadEndpoint = ep;
-                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) &&
-                        (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
-                    Log.d(TAG,"Found writing endpoint");
-                    mWriteEndpoint = ep;
-                }
-
-
-                if ((mControlEndpoint != null) &&
-                    (mReadEndpoint != null) &&
-                    (mWriteEndpoint != null)) {
-                    Log.d(TAG,"Found all required endpoints");
-                    break;
-                }
-            }
-
-            if ((mControlEndpoint == null) ||
-                    (mReadEndpoint == null) ||
-                    (mWriteEndpoint == null)) {
-                Log.d(TAG,"Could not establish all endpoints");
-                throw new IOException("Could not establish all endpoints");
-            }
-        }
-
-        private void openInterface() throws IOException {
-            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());
-
-            mControlInterface = null;
-            mDataInterface = null;
-            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
-                UsbInterface usbInterface = mDevice.getInterface(i);
-                if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM) {
-                    mControlIndex = i;
-                    mControlInterface = usbInterface;
-                }
-                if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
-                    mDataInterface = usbInterface;
-                }
-            }
-
-            if(mControlInterface == null) {
-                throw new IOException("no control interface.");
-            }
-            Log.d(TAG, "Control iface=" + mControlInterface);
-
-            if (!mConnection.claimInterface(mControlInterface, true)) {
-                throw new IOException("Could not claim control interface.");
-            }
-
-            mControlEndpoint = mControlInterface.getEndpoint(0);
-            if (mControlEndpoint.getDirection() != UsbConstants.USB_DIR_IN || mControlEndpoint.getType() != UsbConstants.USB_ENDPOINT_XFER_INT) {
-                throw new IOException("invalid control endpoint");
-            }
-
-            if(mDataInterface == null) {
-                throw new IOException("no data interface.");
-            }
-            Log.d(TAG, "data iface=" + mDataInterface);
-
-            if (!mConnection.claimInterface(mDataInterface, true)) {
-                throw new IOException("Could not claim data interface.");
-            }
-
-            mReadEndpoint = null;
-            mWriteEndpoint = null;
-            for (int i = 0; i < mDataInterface.getEndpointCount(); i++) {
-                UsbEndpoint ep = mDataInterface.getEndpoint(i);
-                if (ep.getDirection() == UsbConstants.USB_DIR_IN && ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
-                    mReadEndpoint = ep;
-                if (ep.getDirection() == UsbConstants.USB_DIR_OUT && ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
-                    mWriteEndpoint = ep;
-            }
-            if (mReadEndpoint == null || mWriteEndpoint == null) {
-                throw new IOException("Could not get read&write endpoints.");
-            }
-        }
-
-        private int sendAcmControlMessage(int request, int value, byte[] buf) throws IOException {
-            int len = mConnection.controlTransfer(
-                    USB_RT_ACM, request, value, mControlIndex, buf, buf != null ? buf.length : 0, 5000);
-            if(len < 0) {
-                throw new IOException("controlTransfer failed.");
-            }
-            return len;
-        }
-
-        @Override
-        public void close() throws IOException {
-            if (mConnection == null) {
-                throw new IOException("Already closed");
-            }
-            mConnection.close();
-            mConnection = null;
-        }
-
-        @Override
-        public int read(byte[] dest, int timeoutMillis) throws IOException {
-            final UsbRequest request = new UsbRequest();
-            try {
-                request.initialize(mConnection, mReadEndpoint);
-                final ByteBuffer buf = ByteBuffer.wrap(dest);
-                if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
-                }
-
-                final UsbRequest response = mConnection.requestWait();
-                if (response == null) {
-                    throw new IOException("Null response");
-                }
-
-                final int nread = buf.position();
-                if (nread > 0) {
-                    //Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, dest.length)));
-                    return nread;
-                } else {
-                    return 0;
-                }
-            } finally {
-                request.close();
-            }
-        }
-
-        @Override
-        public int write(byte[] src, int timeoutMillis) throws IOException {
-            // TODO(mikey): Nearly identical to FtdiSerial write. Refactor.
-            int offset = 0;
-
-            while (offset < src.length) {
-                final int writeLength;
-                final int amtWritten;
-
-                synchronized (mWriteBufferLock) {
-                    final byte[] writeBuffer;
-
-                    writeLength = Math.min(src.length - offset, mWriteBuffer.length);
-                    if (offset == 0) {
-                        writeBuffer = src;
-                    } else {
-                        // bulkTransfer does not support offsets, make a copy.
-                        System.arraycopy(src, offset, mWriteBuffer, 0, writeLength);
-                        writeBuffer = mWriteBuffer;
-                    }
-
-                    amtWritten = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, writeLength,
-                            timeoutMillis);
-                }
-                if (amtWritten <= 0) {
-                    throw new IOException("Error writing " + writeLength
-                            + " bytes at offset " + offset + " length=" + src.length);
-                }
-
-                Log.d(TAG, "Wrote amt=" + amtWritten + " attempted=" + writeLength);
-                offset += amtWritten;
-            }
-            return offset;
-        }
-
-        @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
-            byte stopBitsByte;
-            switch (stopBits) {
-                case STOPBITS_1: stopBitsByte = 0; break;
-                case STOPBITS_1_5: stopBitsByte = 1; break;
-                case STOPBITS_2: stopBitsByte = 2; break;
-                default: throw new IllegalArgumentException("Bad value for stopBits: " + stopBits);
-            }
-
-            byte parityBitesByte;
-            switch (parity) {
-                case PARITY_NONE: parityBitesByte = 0; break;
-                case PARITY_ODD: parityBitesByte = 1; break;
-                case PARITY_EVEN: parityBitesByte = 2; break;
-                case PARITY_MARK: parityBitesByte = 3; break;
-                case PARITY_SPACE: parityBitesByte = 4; break;
-                default: throw new IllegalArgumentException("Bad value for parity: " + parity);
-            }
-
-            byte[] msg = {
-                    (byte) ( baudRate & 0xff),
-                    (byte) ((baudRate >> 8 ) & 0xff),
-                    (byte) ((baudRate >> 16) & 0xff),
-                    (byte) ((baudRate >> 24) & 0xff),
-                    stopBitsByte,
-                    parityBitesByte,
-                    (byte) dataBits};
-            sendAcmControlMessage(SET_LINE_CODING, 0, msg);
-        }
-
-        @Override
-        public boolean getCD() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getCTS() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getDSR() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getDTR() throws IOException {
-            return mDtr;
-        }
-
-        @Override
-        public void setDTR(boolean value) throws IOException {
-            mDtr = value;
-            setDtrRts();
-        }
-
-        @Override
-        public boolean getRI() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getRTS() throws IOException {
-            return mRts;
-        }
-
-        @Override
-        public void setRTS(boolean value) throws IOException {
-            mRts = value;
-            setDtrRts();
-        }
-
-        private void setDtrRts() throws IOException {
-            int value = (mRts ? 0x2 : 0) | (mDtr ? 0x1 : 0);
-            sendAcmControlMessage(SET_CONTROL_LINE_STATE, value, null);
-        }
-
-    }
-
-    public static Map<Integer, int[]> getSupportedDevices() {
-        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<Integer, int[]>();
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_ARDUINO),
-                new int[] {
-                        UsbId.ARDUINO_UNO,
-                        UsbId.ARDUINO_UNO_R3,
-                        UsbId.ARDUINO_MEGA_2560,
-                        UsbId.ARDUINO_MEGA_2560_R3,
-                        UsbId.ARDUINO_SERIAL_ADAPTER,
-                        UsbId.ARDUINO_SERIAL_ADAPTER_R3,
-                        UsbId.ARDUINO_MEGA_ADK,
-                        UsbId.ARDUINO_MEGA_ADK_R3,
-                        UsbId.ARDUINO_LEONARDO,
-                        UsbId.ARDUINO_MICRO,
-                });
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_VAN_OOIJEN_TECH),
-                new int[] {
-                    UsbId.VAN_OOIJEN_TECH_TEENSYDUINO_SERIAL,
-                });
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_ATMEL),
-                new int[] {
-                    UsbId.ATMEL_LUFA_CDC_DEMO_APP,
-                });
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_LEAFLABS),
-                new int[] {
-                    UsbId.LEAFLABS_MAPLE,
-                });
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_ARM),
-                new int[] {
-                    UsbId.ARM_MBED,
-                });
-        return supportedDevices;
-    }
-
-}
+/* Copyright 2011-2013 Google Inc.
+ * Copyright 2013 mike wakerly <opensource@hoho.com>
+ *
+ * Project home page: https://github.com/mik3y/usb-serial-for-android
+ */
+
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+import android.util.Log;
+
+import com.hoho.android.usbserial.util.HexDump;
+import com.hoho.android.usbserial.util.UsbUtils;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * USB CDC/ACM serial driver implementation.
+ *
+ * @author mike wakerly (opensource@hoho.com)
+ * @see <a
+ *      href="http://www.usb.org/developers/devclass_docs/usbcdc11.pdf">Universal
+ *      Serial Bus Class Definitions for Communication Devices, v1.1</a>
+ */
+public class CdcAcmSerialDriver implements UsbSerialDriver {
+
+    public static final int USB_SUBCLASS_ACM = 2;
+
+    private final String TAG = CdcAcmSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final List<UsbSerialPort> mPorts;
+
+    public CdcAcmSerialDriver(UsbDevice device) {
+        mDevice = device;
+        mPorts = new ArrayList<>();
+        int ports = countPorts(device);
+        for (int port = 0; port < ports; port++) {
+            mPorts.add(new CdcAcmSerialPort(mDevice, port));
+        }
+        if (mPorts.size() == 0) {
+            mPorts.add(new CdcAcmSerialPort(mDevice, -1));
+        }
+    }
+
+    @SuppressWarnings({"unused"})
+    public static boolean probe(UsbDevice device) {
+        return countPorts(device) > 0;
+    }
+
+    private static int countPorts(UsbDevice device) {
+        int controlInterfaceCount = 0;
+        int dataInterfaceCount = 0;
+        for (int i = 0; i < device.getInterfaceCount(); i++) {
+            if (device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                    device.getInterface(i).getInterfaceSubclass() == USB_SUBCLASS_ACM)
+                controlInterfaceCount++;
+            if (device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA)
+                dataInterfaceCount++;
+        }
+        return Math.min(controlInterfaceCount, dataInterfaceCount);
+    }
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return mPorts;
+    }
+
+    public class CdcAcmSerialPort extends CommonUsbSerialPort {
+
+        private UsbInterface mControlInterface;
+        private UsbInterface mDataInterface;
+
+        private UsbEndpoint mControlEndpoint;
+
+        private int mControlIndex;
+
+        private boolean mRts = false;
+        private boolean mDtr = false;
+
+        private static final int USB_RECIP_INTERFACE = 0x01;
+        private static final int USB_RT_ACM = UsbConstants.USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+
+        private static final int SET_LINE_CODING = 0x20;  // USB CDC 1.1 section 6.2
+        private static final int GET_LINE_CODING = 0x21;
+        private static final int SET_CONTROL_LINE_STATE = 0x22;
+        private static final int SEND_BREAK = 0x23;
+
+        public CdcAcmSerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return CdcAcmSerialDriver.this;
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            Log.d(TAG, "interfaces:");
+            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                Log.d(TAG, mDevice.getInterface(i).toString());
+            }
+            if (mPortNumber == -1) {
+                Log.d(TAG,"device might be castrated ACM device, trying single interface logic");
+                openSingleInterface();
+            } else {
+                Log.d(TAG,"trying default interface logic");
+                openInterface();
+            }
+        }
+
+        private void openSingleInterface() throws IOException {
+            // the following code is inspired by the cdc-acm driver in the linux kernel
+
+            mControlIndex = 0;
+            mControlInterface = mDevice.getInterface(0);
+            mDataInterface = mDevice.getInterface(0);
+            if (!mConnection.claimInterface(mControlInterface, true)) {
+                throw new IOException("Could not claim shared control/data interface");
+            }
+
+            for (int i = 0; i < mControlInterface.getEndpointCount(); ++i) {
+                UsbEndpoint ep = mControlInterface.getEndpoint(i);
+                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_INT)) {
+                    mControlEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mReadEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mWriteEndpoint = ep;
+                }
+            }
+            if (mControlEndpoint == null) {
+                throw new IOException("No control endpoint");
+            }
+        }
+
+        private void openInterface() throws IOException {
+
+            mControlInterface = null;
+            mDataInterface = null;
+            int j = getInterfaceIdFromDescriptors();
+            Log.d(TAG, "interface count=" + mDevice.getInterfaceCount() + ", IAD=" + j);
+            if (j >= 0) {
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                    UsbInterface usbInterface = mDevice.getInterface(i);
+                    if (usbInterface.getId() == j || usbInterface.getId() == j+1) {
+                        if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                                usbInterface.getInterfaceSubclass() == USB_SUBCLASS_ACM) {
+                            mControlIndex = usbInterface.getId();
+                            mControlInterface = usbInterface;
+                        }
+                        if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
+                            mDataInterface = usbInterface;
+                        }
+                    }
+                }
+            }
+            if (mControlInterface == null || mDataInterface == null) {
+                Log.d(TAG, "no IAD fallback");
+                int controlInterfaceCount = 0;
+                int dataInterfaceCount = 0;
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                    UsbInterface usbInterface = mDevice.getInterface(i);
+                    if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                            usbInterface.getInterfaceSubclass() == USB_SUBCLASS_ACM) {
+                        if (controlInterfaceCount == mPortNumber) {
+                            mControlIndex = usbInterface.getId();
+                            mControlInterface = usbInterface;
+                        }
+                        controlInterfaceCount++;
+                    }
+                    if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
+                        if (dataInterfaceCount == mPortNumber) {
+                            mDataInterface = usbInterface;
+                        }
+                        dataInterfaceCount++;
+                    }
+                }
+            }
+
+            if(mControlInterface == null) {
+                throw new IOException("No control interface");
+            }
+            Log.d(TAG, "Control interface id " + mControlInterface.getId());
+
+            if (!mConnection.claimInterface(mControlInterface, true)) {
+                throw new IOException("Could not claim control interface");
+            }
+            mControlEndpoint = mControlInterface.getEndpoint(0);
+            if (mControlEndpoint.getDirection() != UsbConstants.USB_DIR_IN || mControlEndpoint.getType() != UsbConstants.USB_ENDPOINT_XFER_INT) {
+                throw new IOException("Invalid control endpoint");
+            }
+
+            if(mDataInterface == null) {
+                throw new IOException("No data interface");
+            }
+            Log.d(TAG, "data interface id " + mDataInterface.getId());
+            if (!mConnection.claimInterface(mDataInterface, true)) {
+                throw new IOException("Could not claim data interface");
+            }
+            for (int i = 0; i < mDataInterface.getEndpointCount(); i++) {
+                UsbEndpoint ep = mDataInterface.getEndpoint(i);
+                if (ep.getDirection() == UsbConstants.USB_DIR_IN && ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
+                    mReadEndpoint = ep;
+                if (ep.getDirection() == UsbConstants.USB_DIR_OUT && ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
+                    mWriteEndpoint = ep;
+            }
+        }
+
+        private int getInterfaceIdFromDescriptors() {
+            ArrayList<byte[]> descriptors = UsbUtils.getDescriptors(mConnection);
+            Log.d(TAG, "USB descriptor:");
+            for(byte[] descriptor : descriptors)
+                Log.d(TAG, HexDump.toHexString(descriptor));
+
+            if (descriptors.size() > 0 &&
+                    descriptors.get(0).length == 18 &&
+                    descriptors.get(0)[1] == 1 && // bDescriptorType
+                    descriptors.get(0)[4] == (byte)(UsbConstants.USB_CLASS_MISC) && //bDeviceClass
+                    descriptors.get(0)[5] == 2 && // bDeviceSubClass
+                    descriptors.get(0)[6] == 1) { // bDeviceProtocol
+                // is IAD device, see https://www.usb.org/sites/default/files/iadclasscode_r10.pdf
+                int port = -1;
+                for (int d = 1; d < descriptors.size(); d++) {
+                    if (descriptors.get(d).length == 8 &&
+                            descriptors.get(d)[1] == 0x0b && // bDescriptorType == IAD
+                            descriptors.get(d)[4] == UsbConstants.USB_CLASS_COMM && // bFunctionClass == CDC
+                            descriptors.get(d)[5] == USB_SUBCLASS_ACM) { // bFunctionSubClass == ACM
+                        port++;
+                        if (port == mPortNumber &&
+                                descriptors.get(d)[3] == 2) { // bInterfaceCount
+                            return descriptors.get(d)[2]; // bFirstInterface
+                        }
+                    }
+                }
+            }
+            return -1;
+        }
+
+        private int sendAcmControlMessage(int request, int value, byte[] buf) throws IOException {
+            int len = mConnection.controlTransfer(
+                    USB_RT_ACM, request, value, mControlIndex, buf, buf != null ? buf.length : 0, 5000);
+            if(len < 0) {
+                throw new IOException("controlTransfer failed");
+            }
+            return len;
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                mConnection.releaseInterface(mControlInterface);
+                mConnection.releaseInterface(mDataInterface);
+            } catch(Exception ignored) {}
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            if(dataBits < DATABITS_5 || dataBits > DATABITS_8) {
+                throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }
+            byte stopBitsByte;
+            switch (stopBits) {
+                case STOPBITS_1: stopBitsByte = 0; break;
+                case STOPBITS_1_5: stopBitsByte = 1; break;
+                case STOPBITS_2: stopBitsByte = 2; break;
+                default: throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
+            }
+
+            byte parityBitesByte;
+            switch (parity) {
+                case PARITY_NONE: parityBitesByte = 0; break;
+                case PARITY_ODD: parityBitesByte = 1; break;
+                case PARITY_EVEN: parityBitesByte = 2; break;
+                case PARITY_MARK: parityBitesByte = 3; break;
+                case PARITY_SPACE: parityBitesByte = 4; break;
+                default: throw new IllegalArgumentException("Invalid parity: " + parity);
+            }
+            byte[] msg = {
+                    (byte) ( baudRate & 0xff),
+                    (byte) ((baudRate >> 8 ) & 0xff),
+                    (byte) ((baudRate >> 16) & 0xff),
+                    (byte) ((baudRate >> 24) & 0xff),
+                    stopBitsByte,
+                    parityBitesByte,
+                    (byte) dataBits};
+            sendAcmControlMessage(SET_LINE_CODING, 0, msg);
+        }
+
+        @Override
+        public boolean getDTR() throws IOException {
+            return mDtr;
+        }
+
+        @Override
+        public void setDTR(boolean value) throws IOException {
+            mDtr = value;
+            setDtrRts();
+        }
+
+        @Override
+        public boolean getRTS() throws IOException {
+            return mRts;
+        }
+
+        @Override
+        public void setRTS(boolean value) throws IOException {
+            mRts = value;
+            setDtrRts();
+        }
+
+        private void setDtrRts() throws IOException {
+            int value = (mRts ? 0x2 : 0) | (mDtr ? 0x1 : 0);
+            sendAcmControlMessage(SET_CONTROL_LINE_STATE, value, null);
+        }
+
+        @Override
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            if(mRts) set.add(ControlLine.RTS);
+            if(mDtr) set.add(ControlLine.DTR);
+            return set;
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.of(ControlLine.RTS, ControlLine.DTR);
+        }
+
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            sendAcmControlMessage(SEND_BREAK, value ? 0xffff : 0, null);
+        }
+
+    }
+
+    @SuppressWarnings({"unused"})
+    public static Map<Integer, int[]> getSupportedDevices() {
+        return new LinkedHashMap<>();
+    }
+
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java

@@ -1,19 +1,4 @@
 /* Copyright 2014 Andreas Butti
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
  *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
@@ -22,423 +7,381 @@ package com.hoho.android.usbserial.driver;
 
 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
-import android.hardware.usb.UsbRequest;
 import android.util.Log;
 
+import com.hoho.android.usbserial.BuildConfig;
+
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.util.Collections;
+import java.util.EnumSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-/**
- * Driver for CH340, maybe also working with CH341, but not tested
- * See http://wch-ic.com/product/usb/ch340.asp
- *
- * @author Andreas Butti
- */
 public class Ch34xSerialDriver implements UsbSerialDriver {
 
-	private static final String TAG = Ch34xSerialDriver.class.getSimpleName();
-
-	private final UsbDevice mDevice;
-	private final UsbSerialPort mPort;
-
-	private static final int LCR_ENABLE_RX   = 0x80;
-	private static final int LCR_ENABLE_TX   = 0x40;
-	private static final int LCR_MARK_SPACE  = 0x20;
-	private static final int LCR_PAR_EVEN    = 0x10;
-	private static final int LCR_ENABLE_PAR  = 0x08;
-	private static final int LCR_STOP_BITS_2 = 0x04;
-	private static final int LCR_CS8         = 0x03;
-	private static final int LCR_CS7         = 0x02;
-	private static final int LCR_CS6         = 0x01;
-	private static final int LCR_CS5         = 0x00;
-
-	public Ch34xSerialDriver(UsbDevice device) {
-		mDevice = device;
-		mPort = new Ch340SerialPort(mDevice, 0);
-	}
-
-	@Override
-	public UsbDevice getDevice() {
-		return mDevice;
-	}
-
-	@Override
-	public List<UsbSerialPort> getPorts() {
-		return Collections.singletonList(mPort);
-	}
-
-	public class Ch340SerialPort extends CommonUsbSerialPort {
-
-		private static final int USB_TIMEOUT_MILLIS = 5000;
-
-		private final int DEFAULT_BAUD_RATE = 9600;
-
-		private boolean dtr = false;
-		private boolean rts = false;
-
-		private UsbEndpoint mReadEndpoint;
-		private UsbEndpoint mWriteEndpoint;
-		private UsbRequest mUsbRequest;
-
-		public Ch340SerialPort(UsbDevice device, int portNumber) {
-			super(device, portNumber);
-		}
-
-		@Override
-		public UsbSerialDriver getDriver() {
-			return Ch34xSerialDriver.this;
-		}
-
-		@Override
-		public void open(UsbDeviceConnection connection) throws IOException {
-			if (mConnection != null) {
-				throw new IOException("Already opened.");
-			}
-
-			mConnection = connection;
-			boolean opened = false;
-			try {
-				for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
-					UsbInterface usbIface = mDevice.getInterface(i);
-					if (!mConnection.claimInterface(usbIface, true)) {
-						throw new IOException("Could not claim data interface.");
-					}
-				}
-
-				UsbInterface dataIface = mDevice.getInterface(mDevice.getInterfaceCount() - 1);
-				for (int i = 0; i < dataIface.getEndpointCount(); i++) {
-					UsbEndpoint ep = dataIface.getEndpoint(i);
-					if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
-						if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
-							mReadEndpoint = ep;
-						} else {
-							mWriteEndpoint = ep;
-						}
-					}
-				}
-
-				initialize();
-				setBaudRate(DEFAULT_BAUD_RATE);
-
-				opened = true;
-			} finally {
-				if (!opened) {
-					try {
-						close();
-					} catch (IOException e) {
-						// Ignore IOExceptions during close()
-					}
-				}
-			}
-		}
-
-		@Override
-		public void close() throws IOException {
-			if (mConnection == null) {
-				throw new IOException("Already closed");
-			}
-			synchronized (this) {
-				if (mUsbRequest != null)
-					mUsbRequest.cancel();
-			}
-			try {
-				mConnection.close();
-			} finally {
-				mConnection = null;
-			}
-		}
-
-
-		@Override
-		public int read(byte[] dest, int timeoutMillis) throws IOException {
-			final UsbRequest request = new UsbRequest();
-			try {
-				request.initialize(mConnection, mReadEndpoint);
-				final ByteBuffer buf = ByteBuffer.wrap(dest);
-				if (!request.queue(buf, dest.length)) {
-					throw new IOException("Error queueing request.");
-				}
-				mUsbRequest = request;
-				final UsbRequest response = mConnection.requestWait();
-				synchronized (this) {
-					mUsbRequest = null;
-				}
-				if (response == null) {
-					throw new IOException("Null response");
-				}
-
-				final int nread = buf.position();
-				if (nread > 0) {
-					//Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, dest.length)));
-					return nread;
-				} else {
-					return 0;
-				}
-			} finally {
-				mUsbRequest = null;
-				request.close();
-			}
-		}
-
-		@Override
-		public int write(byte[] src, int timeoutMillis) throws IOException {
-			int offset = 0;
-
-			while (offset < src.length) {
-				final int writeLength;
-				final int amtWritten;
-
-				synchronized (mWriteBufferLock) {
-					final byte[] writeBuffer;
-
-					writeLength = Math.min(src.length - offset, mWriteBuffer.length);
-					if (offset == 0) {
-						writeBuffer = src;
-					} else {
-						// bulkTransfer does not support offsets, make a copy.
-						System.arraycopy(src, offset, mWriteBuffer, 0, writeLength);
-						writeBuffer = mWriteBuffer;
-					}
-
-					amtWritten = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, writeLength,
-							timeoutMillis);
-				}
-				if (amtWritten <= 0) {
-					throw new IOException("Error writing " + writeLength
-							+ " bytes at offset " + offset + " length=" + src.length);
-				}
-
-				Log.d(TAG, "Wrote amt=" + amtWritten + " attempted=" + writeLength);
-				offset += amtWritten;
-			}
-			return offset;
-		}
-
-		private int controlOut(int request, int value, int index) {
-			final int REQTYPE_HOST_TO_DEVICE = 0x41;
-			return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request,
-					value, index, null, 0, USB_TIMEOUT_MILLIS);
-		}
-
-
-		private int controlIn(int request, int value, int index, byte[] buffer) {
-			final int REQTYPE_HOST_TO_DEVICE = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_IN;
-			return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request,
-					value, index, buffer, buffer.length, USB_TIMEOUT_MILLIS);
-		}
-
-
-		private void checkState(String msg, int request, int value, int[] expected) throws IOException {
-			byte[] buffer = new byte[expected.length];
-			int ret = controlIn(request, value, 0, buffer);
-
-			if (ret < 0) {
-				throw new IOException("Faild send cmd [" + msg + "]");
-			}
-
-			if (ret != expected.length) {
-				throw new IOException("Expected " + expected.length + " bytes, but get " + ret + " [" + msg + "]");
-			}
-
-			for (int i = 0; i < expected.length; i++) {
-				if (expected[i] == -1) {
-					continue;
-				}
-
-				int current = buffer[i] & 0xff;
-				if (expected[i] != current) {
-					throw new IOException("Expected 0x" + Integer.toHexString(expected[i]) + " bytes, but get 0x" + Integer.toHexString(current) + " [" + msg + "]");
-				}
-			}
-		}
-
-		private void writeHandshakeByte() throws IOException {
-			if (controlOut(0xa4, ~((dtr ? 1 << 5 : 0) | (rts ? 1 << 6 : 0)), 0) < 0) {
-				throw new IOException("Faild to set handshake byte");
-			}
-		}
-
-		private void initialize() throws IOException {
-			checkState("init #1", 0x5f, 0, new int[]{-1 /* 0x27, 0x30 */, 0x00});
-
-			if (controlOut(0xa1, 0, 0) < 0) {
-				throw new IOException("init failed! #2");
-			}
-
-			setBaudRate(DEFAULT_BAUD_RATE);
-
-			checkState("init #4", 0x95, 0x2518, new int[]{-1 /* 0x56, c3*/, 0x00});
-
-			if (controlOut(0x9a, 0x2518, LCR_ENABLE_RX | LCR_ENABLE_TX | LCR_CS8) < 0) {
-				throw new IOException("init failed! #5");
-			}
-
-			checkState("init #6", 0x95, 0x0706, new int[]{0xff, 0xee});
-
-			if (controlOut(0xa1, 0x501f, 0xd90a) < 0) {
-				throw new IOException("init failed! #7");
-			}
-
-			setBaudRate(DEFAULT_BAUD_RATE);
-
-			writeHandshakeByte();
-
-			checkState("init #10", 0x95, 0x0706, new int[]{-1/* 0x9f, 0xff*/, 0xee});
-		}
-
-
-		private void setBaudRate(int baudRate) throws IOException {
-			final long CH341_BAUDBASE_FACTOR = 1532620800;
-			final int CH341_BAUDBASE_DIVMAX = 3;
-
-			long factor = CH341_BAUDBASE_FACTOR / baudRate;
-			int divisor = CH341_BAUDBASE_DIVMAX;
-
-			while ((factor > 0xfff0) && divisor > 0) {
-				factor >>= 3;
-				divisor--;
-					}
-
-			if (factor > 0xfff0) {
-				throw new IOException("Baudrate " + baudRate + " not supported");
-			}
-
-			factor = 0x10000 - factor;
-
-			int ret = controlOut(0x9a, 0x1312, (int) ((factor & 0xff00) | divisor));
-			if (ret < 0) {
-				throw new IOException("Error setting baud rate. #1)");
-			}
-
-			ret = controlOut(0x9a, 0x0f2c, (int) (factor & 0xff));
-			if (ret < 0) {
-				throw new IOException("Error setting baud rate. #2");
-			}
-		}
-
-		@Override
-		public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
-				throws IOException {
-			setBaudRate(baudRate);
-
-			int lcr = LCR_ENABLE_RX | LCR_ENABLE_TX;
-
-			switch (dataBits) {
-				case DATABITS_5:
-					lcr |= LCR_CS5;
-					break;
-				case DATABITS_6:
-					lcr |= LCR_CS6;
-					break;
-				case DATABITS_7:
-					lcr |= LCR_CS7;
-					break;
-				case DATABITS_8:
-					lcr |= LCR_CS8;
-					break;
-				default:
-					throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
-			}
-
-			switch (parity) {
-				case PARITY_NONE:
-					break;
-				case PARITY_ODD:
-					lcr |= LCR_ENABLE_PAR;
-					break;
-				case PARITY_EVEN:
-					lcr |= LCR_ENABLE_PAR | LCR_PAR_EVEN;
-					break;
-				case PARITY_MARK:
-					lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE;
-					break;
-				case PARITY_SPACE:
-					lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE | LCR_PAR_EVEN;
-					break;
-				default:
-					throw new IllegalArgumentException("Unknown parity value: " + parity);
-			}
-
-			switch (stopBits) {
-				case STOPBITS_1:
-					break;
-				case STOPBITS_1_5:
-					throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
-				case STOPBITS_2:
-					lcr |= LCR_STOP_BITS_2;
-					break;
-				default:
-					throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
-			}
-
-			int ret = controlOut(0x9a, 0x2518, lcr);
-			if (ret < 0) {
-				throw new IOException("Error setting control byte");
-			}
-		}
-
-		@Override
-		public boolean getCD() throws IOException {
-			return false;
-		}
-
-		@Override
-		public boolean getCTS() throws IOException {
-			return false;
-		}
-
-		@Override
-		public boolean getDSR() throws IOException {
-			return false;
-		}
-
-		@Override
-		public boolean getDTR() throws IOException {
-			return dtr;
-		}
-
-		@Override
-		public void setDTR(boolean value) throws IOException {
-			dtr = value;
-			writeHandshakeByte();
-		}
-
-		@Override
-		public boolean getRI() throws IOException {
-			return false;
-		}
-
-		@Override
-		public boolean getRTS() throws IOException {
-			return rts;
-		}
-
-		@Override
-		public void setRTS(boolean value) throws IOException {
-			rts = value;
-			writeHandshakeByte();
-		}
-
-		@Override
-		public boolean purgeHwBuffers(boolean purgeReadBuffers, boolean purgeWriteBuffers) throws IOException {
-			return true;
-		}
-
-	}
-
-	public static Map<Integer, int[]> getSupportedDevices() {
-		final Map<Integer, int[]> supportedDevices = new LinkedHashMap<Integer, int[]>();
-		supportedDevices.put(UsbId.VENDOR_QINHENG, new int[]{
-				UsbId.QINHENG_HL340
-		});
-		return supportedDevices;
-	}
+    private static final String TAG = Ch34xSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final UsbSerialPort mPort;
+
+    private static final int LCR_ENABLE_RX   = 0x80;
+    private static final int LCR_ENABLE_TX   = 0x40;
+    private static final int LCR_MARK_SPACE  = 0x20;
+    private static final int LCR_PAR_EVEN    = 0x10;
+    private static final int LCR_ENABLE_PAR  = 0x08;
+    private static final int LCR_STOP_BITS_2 = 0x04;
+    private static final int LCR_CS8         = 0x03;
+    private static final int LCR_CS7         = 0x02;
+    private static final int LCR_CS6         = 0x01;
+    private static final int LCR_CS5         = 0x00;
+
+    private static final int GCL_CTS = 0x01;
+    private static final int GCL_DSR = 0x02;
+    private static final int GCL_RI  = 0x04;
+    private static final int GCL_CD  = 0x08;
+    private static final int SCL_DTR = 0x20;
+    private static final int SCL_RTS = 0x40;
+
+    public Ch34xSerialDriver(UsbDevice device) {
+        mDevice = device;
+        mPort = new Ch340SerialPort(mDevice, 0);
+    }
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return Collections.singletonList(mPort);
+    }
+
+    public class Ch340SerialPort extends CommonUsbSerialPort {
+
+        private static final int USB_TIMEOUT_MILLIS = 5000;
+
+        private final int DEFAULT_BAUD_RATE = 9600;
+
+        private boolean dtr = false;
+        private boolean rts = false;
+
+        public Ch340SerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return Ch34xSerialDriver.this;
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                UsbInterface usbIface = mDevice.getInterface(i);
+                if (!mConnection.claimInterface(usbIface, true)) {
+                    throw new IOException("Could not claim data interface");
+                }
+            }
+
+            UsbInterface dataIface = mDevice.getInterface(mDevice.getInterfaceCount() - 1);
+            for (int i = 0; i < dataIface.getEndpointCount(); i++) {
+                UsbEndpoint ep = dataIface.getEndpoint(i);
+                if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
+                    if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
+                        mReadEndpoint = ep;
+                    } else {
+                        mWriteEndpoint = ep;
+                    }
+                }
+            }
+
+            initialize();
+            setBaudRate(DEFAULT_BAUD_RATE);
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++)
+                    mConnection.releaseInterface(mDevice.getInterface(i));
+            } catch(Exception ignored) {}
+        }
+
+        private int controlOut(int request, int value, int index) {
+            final int REQTYPE_HOST_TO_DEVICE = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_OUT;
+            return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request,
+                    value, index, null, 0, USB_TIMEOUT_MILLIS);
+        }
+
+
+        private int controlIn(int request, int value, int index, byte[] buffer) {
+            final int REQTYPE_DEVICE_TO_HOST = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_IN;
+            return mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, request,
+                    value, index, buffer, buffer.length, USB_TIMEOUT_MILLIS);
+        }
+
+
+        private void checkState(String msg, int request, int value, int[] expected) throws IOException {
+            byte[] buffer = new byte[expected.length];
+            int ret = controlIn(request, value, 0, buffer);
+
+            if (ret < 0) {
+                throw new IOException("Failed send cmd [" + msg + "]");
+            }
+
+            if (ret != expected.length) {
+                throw new IOException("Expected " + expected.length + " bytes, but get " + ret + " [" + msg + "]");
+            }
+
+            for (int i = 0; i < expected.length; i++) {
+                if (expected[i] == -1) {
+                    continue;
+                }
+
+                int current = buffer[i] & 0xff;
+                if (expected[i] != current) {
+                    throw new IOException("Expected 0x" + Integer.toHexString(expected[i]) + " byte, but get 0x" + Integer.toHexString(current) + " [" + msg + "]");
+                }
+            }
+        }
+
+        private void setControlLines() throws IOException {
+            if (controlOut(0xa4, ~((dtr ? SCL_DTR : 0) | (rts ? SCL_RTS : 0)), 0) < 0) {
+                throw new IOException("Failed to set control lines");
+            }
+        }
+
+        private byte getStatus() throws IOException {
+            byte[] buffer = new byte[2];
+            int ret = controlIn(0x95, 0x0706, 0, buffer);
+            if (ret < 0)
+                throw new IOException("Error getting control lines");
+            return buffer[0];
+        }
+
+        private void initialize() throws IOException {
+            checkState("init #1", 0x5f, 0, new int[]{-1 /* 0x27, 0x30 */, 0x00});
+
+            if (controlOut(0xa1, 0, 0) < 0) {
+                throw new IOException("Init failed: #2");
+            }
+
+            setBaudRate(DEFAULT_BAUD_RATE);
+
+            checkState("init #4", 0x95, 0x2518, new int[]{-1 /* 0x56, c3*/, 0x00});
+
+            if (controlOut(0x9a, 0x2518, LCR_ENABLE_RX | LCR_ENABLE_TX | LCR_CS8) < 0) {
+                throw new IOException("Init failed: #5");
+            }
+
+            checkState("init #6", 0x95, 0x0706, new int[]{-1/*0xf?*/, -1/*0xec,0xee*/});
+
+            if (controlOut(0xa1, 0x501f, 0xd90a) < 0) {
+                throw new IOException("Init failed: #7");
+            }
+
+            setBaudRate(DEFAULT_BAUD_RATE);
+
+            setControlLines();
+
+            checkState("init #10", 0x95, 0x0706, new int[]{-1/* 0x9f, 0xff*/, -1/*0xec,0xee*/});
+        }
+
+
+        private void setBaudRate(int baudRate) throws IOException {
+            long factor;
+            long divisor;
+
+            if (baudRate == 921600) {
+                divisor = 7;
+                factor = 0xf300;
+            } else {
+                final long BAUDBASE_FACTOR = 1532620800;
+                final int BAUDBASE_DIVMAX = 3;
+
+                if(BuildConfig.DEBUG && (baudRate & (3<<29)) == (1<<29))
+                    baudRate &= ~(1<<29); // for testing purpose bypass dedicated baud rate handling
+                factor = BAUDBASE_FACTOR / baudRate;
+                divisor = BAUDBASE_DIVMAX;
+                while ((factor > 0xfff0) && divisor > 0) {
+                    factor >>= 3;
+                    divisor--;
+                }
+                if (factor > 0xfff0) {
+                    throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
+                }
+                factor = 0x10000 - factor;
+            }
+
+            divisor |= 0x0080; // else ch341a waits until buffer full
+            int val1 = (int) ((factor & 0xff00) | divisor);
+            int val2 = (int) (factor & 0xff);
+            Log.d(TAG, String.format("baud rate=%d, 0x1312=0x%04x, 0x0f2c=0x%04x", baudRate, val1, val2));
+            int ret = controlOut(0x9a, 0x1312, val1);
+            if (ret < 0) {
+                throw new IOException("Error setting baud rate: #1)");
+            }
+            ret = controlOut(0x9a, 0x0f2c, val2);
+            if (ret < 0) {
+                throw new IOException("Error setting baud rate: #2");
+            }
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            setBaudRate(baudRate);
+
+            int lcr = LCR_ENABLE_RX | LCR_ENABLE_TX;
+
+            switch (dataBits) {
+                case DATABITS_5:
+                    lcr |= LCR_CS5;
+                    break;
+                case DATABITS_6:
+                    lcr |= LCR_CS6;
+                    break;
+                case DATABITS_7:
+                    lcr |= LCR_CS7;
+                    break;
+                case DATABITS_8:
+                    lcr |= LCR_CS8;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }
+
+            switch (parity) {
+                case PARITY_NONE:
+                    break;
+                case PARITY_ODD:
+                    lcr |= LCR_ENABLE_PAR;
+                    break;
+                case PARITY_EVEN:
+                    lcr |= LCR_ENABLE_PAR | LCR_PAR_EVEN;
+                    break;
+                case PARITY_MARK:
+                    lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE;
+                    break;
+                case PARITY_SPACE:
+                    lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE | LCR_PAR_EVEN;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
+            }
+
+            switch (stopBits) {
+                case STOPBITS_1:
+                    break;
+                case STOPBITS_1_5:
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
+                case STOPBITS_2:
+                    lcr |= LCR_STOP_BITS_2;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
+            }
+
+            int ret = controlOut(0x9a, 0x2518, lcr);
+            if (ret < 0) {
+                throw new IOException("Error setting control byte");
+            }
+        }
+
+        @Override
+        public boolean getCD() throws IOException {
+            return (getStatus() & GCL_CD) == 0;
+        }
+
+        @Override
+        public boolean getCTS() throws IOException {
+            return (getStatus() & GCL_CTS) == 0;
+        }
+
+        @Override
+        public boolean getDSR() throws IOException {
+            return (getStatus() & GCL_DSR) == 0;
+        }
+
+        @Override
+        public boolean getDTR() throws IOException {
+            return dtr;
+        }
+
+        @Override
+        public void setDTR(boolean value) throws IOException {
+            dtr = value;
+            setControlLines();
+        }
+
+        @Override
+        public boolean getRI() throws IOException {
+            return (getStatus() & GCL_RI) == 0;
+        }
+
+        @Override
+        public boolean getRTS() throws IOException {
+            return rts;
+        }
+
+        @Override
+        public void setRTS(boolean value) throws IOException {
+            rts = value;
+            setControlLines();
+        }
+
+        @Override
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            int status = getStatus();
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            if(rts) set.add(ControlLine.RTS);
+            if((status & GCL_CTS) == 0) set.add(ControlLine.CTS);
+            if(dtr) set.add(ControlLine.DTR);
+            if((status & GCL_DSR) == 0) set.add(ControlLine.DSR);
+            if((status & GCL_CD) == 0) set.add(ControlLine.CD);
+            if((status & GCL_RI) == 0) set.add(ControlLine.RI);
+            return set;
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.allOf(ControlLine.class);
+        }
+
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            byte[] req = new byte[2];
+            if(controlIn(0x95, 0x1805, 0, req) < 0) {
+                throw new IOException("Error getting BREAK condition");
+            }
+            if(value) {
+                req[0] &= ~1;
+                req[1] &= ~0x40;
+            } else {
+                req[0] |= 1;
+                req[1] |= 0x40;
+            }
+            int val = (req[1] & 0xff) << 8 | (req[0] & 0xff);
+            if(controlOut(0x9a, 0x1805, val) < 0) {
+                throw new IOException("Error setting BREAK condition");
+            }
+        }
+    }
+
+    @SuppressWarnings({"unused"})
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_QINHENG, new int[]{
+                UsbId.QINHENG_CH340,
+                UsbId.QINHENG_CH341A,
+        });
+        return supportedDevices;
+    }
 
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ChromeCcdSerialDriver.java

@@ -0,0 +1,91 @@
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+import android.util.Log;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.ArrayList;
+
+public class ChromeCcdSerialDriver implements UsbSerialDriver{
+
+    private final String TAG = ChromeCcdSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final List<UsbSerialPort> mPorts;
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return mPorts;
+    }
+
+    public ChromeCcdSerialDriver(UsbDevice mDevice) {
+        this.mDevice = mDevice;
+        mPorts = new ArrayList<UsbSerialPort>();
+        for (int i = 0; i < 3; i++)
+            mPorts.add(new ChromeCcdSerialPort(mDevice, i));
+    }
+
+    public class ChromeCcdSerialPort extends CommonUsbSerialPort {
+        private UsbInterface mDataInterface;
+
+        public ChromeCcdSerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());
+            mDataInterface = mDevice.getInterface(mPortNumber);
+            if (!mConnection.claimInterface(mDataInterface, true)) {
+                throw new IOException("Could not claim shared control/data interface");
+            }
+            Log.d(TAG, "endpoint count=" + mDataInterface.getEndpointCount());
+            for (int i = 0; i < mDataInterface.getEndpointCount(); ++i) {
+                UsbEndpoint ep = mDataInterface.getEndpoint(i);
+                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mReadEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mWriteEndpoint = ep;
+                }
+            }
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                mConnection.releaseInterface(mDataInterface);
+            } catch(Exception ignored) {}
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return ChromeCcdSerialDriver.this;
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_GOOGLE, new int[]{
+                UsbId.GOOGLE_CR50,
+        });
+        return supportedDevices;
+    }
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java

@@ -1,21 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
@@ -23,42 +8,53 @@ package com.hoho.android.usbserial.driver;
 
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbRequest;
+import android.os.Build;
+import android.util.Log;
+
+import com.hoho.android.usbserial.util.MonotonicClock;
 
 import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.EnumSet;
 
 /**
  * A base class shared by several driver implementations.
  *
  * @author mike wakerly (opensource@hoho.com)
  */
-abstract class CommonUsbSerialPort implements UsbSerialPort {
+public abstract class CommonUsbSerialPort implements UsbSerialPort {
 
-    public static final int DEFAULT_READ_BUFFER_SIZE = 16 * 1024;
-    public static final int DEFAULT_WRITE_BUFFER_SIZE = 16 * 1024;
+    public static boolean DEBUG = false;
+
+    private static final String TAG = CommonUsbSerialPort.class.getSimpleName();
+    private static final int MAX_READ_SIZE = 16 * 1024; // = old bulkTransfer limit prior to Android 9
 
     protected final UsbDevice mDevice;
     protected final int mPortNumber;
 
     // non-null when open()
-    protected UsbDeviceConnection mConnection = null;
+    protected UsbDeviceConnection mConnection;
+    protected UsbEndpoint mReadEndpoint;
+    protected UsbEndpoint mWriteEndpoint;
+    protected UsbRequest mUsbRequest;
+    protected FlowControl mFlowControl = FlowControl.NONE;
 
-    protected final Object mReadBufferLock = new Object();
+    /**
+     * Internal write buffer.
+     *  Guarded by {@link #mWriteBufferLock}.
+     *  Default length = mReadEndpoint.getMaxPacketSize()
+     **/
+    protected byte[] mWriteBuffer;
     protected final Object mWriteBufferLock = new Object();
 
-    /** Internal read buffer.  Guarded by {@link #mReadBufferLock}. */
-    protected byte[] mReadBuffer;
-
-    /** Internal write buffer.  Guarded by {@link #mWriteBufferLock}. */
-    protected byte[] mWriteBuffer;
 
     public CommonUsbSerialPort(UsbDevice device, int portNumber) {
         mDevice = device;
         mPortNumber = portNumber;
-
-        mReadBuffer = new byte[DEFAULT_READ_BUFFER_SIZE];
-        mWriteBuffer = new byte[DEFAULT_WRITE_BUFFER_SIZE];
     }
-    
+
     @Override
     public String toString() {
         return String.format("<%s device_name=%s device_id=%s port_number=%s>",
@@ -66,12 +62,8 @@ abstract class CommonUsbSerialPort implements UsbSerialPort {
                 mDevice.getDeviceId(), mPortNumber);
     }
 
-    /**
-     * Returns the currently-bound USB device.
-     *
-     * @return the device
-     */
-    public final UsbDevice getDevice() {
+    @Override
+    public UsbDevice getDevice() {
         return mDevice;
     }
 
@@ -79,7 +71,13 @@ abstract class CommonUsbSerialPort implements UsbSerialPort {
     public int getPortNumber() {
         return mPortNumber;
     }
-    
+
+    @Override
+    public UsbEndpoint getWriteEndpoint() { return mWriteEndpoint; }
+
+    @Override
+    public UsbEndpoint getReadEndpoint() { return mReadEndpoint; }
+
     /**
      * Returns the device serial number
      *  @return serial number
@@ -89,30 +87,23 @@ abstract class CommonUsbSerialPort implements UsbSerialPort {
         return mConnection.getSerial();
     }
 
-    /**
-     * Sets the size of the internal buffer used to exchange data with the USB
-     * stack for read operations.  Most users should not need to change this.
-     *
-     * @param bufferSize the size in bytes
-     */
-    public final void setReadBufferSize(int bufferSize) {
-        synchronized (mReadBufferLock) {
-            if (bufferSize == mReadBuffer.length) {
-                return;
-            }
-            mReadBuffer = new byte[bufferSize];
-        }
-    }
-
     /**
      * Sets the size of the internal buffer used to exchange data with the USB
      * stack for write operations.  Most users should not need to change this.
      *
-     * @param bufferSize the size in bytes
+     * @param bufferSize the size in bytes, <= 0 resets original size
      */
     public final void setWriteBufferSize(int bufferSize) {
         synchronized (mWriteBufferLock) {
-            if (bufferSize == mWriteBuffer.length) {
+            if (bufferSize <= 0) {
+                if (mWriteEndpoint != null) {
+                    bufferSize = mWriteEndpoint.getMaxPacketSize();
+                } else {
+                    mWriteBuffer = null;
+                    return;
+                }
+            }
+            if (mWriteBuffer != null && bufferSize == mWriteBuffer.length) {
                 return;
             }
             mWriteBuffer = new byte[bufferSize];
@@ -120,48 +111,247 @@ abstract class CommonUsbSerialPort implements UsbSerialPort {
     }
 
     @Override
-    public abstract void open(UsbDeviceConnection connection) throws IOException;
-
-    @Override
-    public abstract void close() throws IOException;
-
-    @Override
-    public abstract int read(final byte[] dest, final int timeoutMillis) throws IOException;
-
-    @Override
-    public abstract int write(final byte[] src, final int timeoutMillis) throws IOException;
-
-    @Override
-    public abstract void setParameters(
-            int baudRate, int dataBits, int stopBits, int parity) throws IOException;
-
-    @Override
-    public abstract boolean getCD() throws IOException;
-
-    @Override
-    public abstract boolean getCTS() throws IOException;
-
-    @Override
-    public abstract boolean getDSR() throws IOException;
-
-    @Override
-    public abstract boolean getDTR() throws IOException;
-
-    @Override
-    public abstract void setDTR(boolean value) throws IOException;
-
-    @Override
-    public abstract boolean getRI() throws IOException;
-
-    @Override
-    public abstract boolean getRTS() throws IOException;
-
-    @Override
-    public abstract void setRTS(boolean value) throws IOException;
-
-    @Override
-    public boolean purgeHwBuffers(boolean flushReadBuffers, boolean flushWriteBuffers) throws IOException {
-        return !flushReadBuffers && !flushWriteBuffers;
+    public void open(UsbDeviceConnection connection) throws IOException {
+        if (mConnection != null) {
+            throw new IOException("Already open");
+        }
+        if(connection == null) {
+            throw new IllegalArgumentException("Connection is null");
+        }
+        mConnection = connection;
+        boolean ok = false;
+        try {
+            openInt();
+            if (mReadEndpoint == null || mWriteEndpoint == null) {
+                throw new IOException("Could not get read & write endpoints");
+            }
+            mUsbRequest = new UsbRequest();
+            mUsbRequest.initialize(mConnection, mReadEndpoint);
+            ok = true;
+        } finally {
+            if (!ok) {
+                try {
+                    close();
+                } catch (Exception ignored) {}
+            }
+        }
     }
 
+    protected abstract void openInt() throws IOException;
+
+    @Override
+    public void close() throws IOException {
+        if (mConnection == null) {
+            throw new IOException("Already closed");
+        }
+        UsbRequest usbRequest = mUsbRequest;
+        mUsbRequest = null;
+        try {
+            usbRequest.cancel();
+        } catch(Exception ignored) {}
+        try {
+            closeInt();
+        } catch(Exception ignored) {}
+        try {
+            mConnection.close();
+        } catch(Exception ignored) {}
+        mConnection = null;
+    }
+
+    protected abstract void closeInt();
+
+    /**
+     * use simple USB request supported by all devices to test if connection is still valid
+     */
+    protected void testConnection(boolean full) throws IOException {
+        testConnection(full, "USB get_status request failed");
+    }
+
+    protected void testConnection(boolean full, String msg) throws IOException {
+        if(mUsbRequest == null) {
+            throw new IOException("Connection closed");
+        }
+        if(!full) {
+            return;
+        }
+        byte[] buf = new byte[2];
+        int len = mConnection.controlTransfer(0x80 /*DEVICE*/, 0 /*GET_STATUS*/, 0, 0, buf, buf.length, 200);
+        if(len < 0)
+            throw new IOException(msg);
+    }
+
+    @Override
+    public int read(final byte[] dest, final int timeout) throws IOException {
+        if(dest.length == 0) {
+            throw new IllegalArgumentException("Read buffer too small");
+        }
+        return read(dest, dest.length, timeout);
+    }
+
+    @Override
+    public int read(final byte[] dest, final int length, final int timeout) throws IOException {return read(dest, length, timeout, true);}
+
+    protected int read(final byte[] dest, int length, final int timeout, boolean testConnection) throws IOException {
+        testConnection(false);
+        if(length <= 0) {
+            throw new IllegalArgumentException("Read length too small");
+        }
+        length = Math.min(length, dest.length);
+        final int nread;
+        if (timeout != 0) {
+            // bulkTransfer will cause data loss with short timeout + high baud rates + continuous transfer
+            //   https://stackoverflow.com/questions/9108548/android-usb-host-bulktransfer-is-losing-data
+            // but mConnection.requestWait(timeout) available since Android 8.0 es even worse,
+            // as it crashes with short timeout, e.g.
+            //   A/libc: Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x276a in tid 29846 (pool-2-thread-1), pid 29618 (.usbserial.test)
+            //     /system/lib64/libusbhost.so (usb_request_wait+192)
+            //     /system/lib64/libandroid_runtime.so (android_hardware_UsbDeviceConnection_request_wait(_JNIEnv*, _jobject*, long)+84)
+            // data loss / crashes were observed with timeout up to 200 msec
+            long endTime = testConnection ? MonotonicClock.millis() + timeout : 0;
+            int readMax = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) ? length : Math.min(length, MAX_READ_SIZE);
+            nread = mConnection.bulkTransfer(mReadEndpoint, dest, readMax, timeout);
+            // Android error propagation is improvable:
+            //  nread == -1 can be: timeout, connection lost, buffer to small, ???
+            if(nread == -1 && testConnection)
+                testConnection(MonotonicClock.millis() < endTime);
+
+        } else {
+            final ByteBuffer buf = ByteBuffer.wrap(dest, 0, length);
+            if (!mUsbRequest.queue(buf, length)) {
+                throw new IOException("Queueing USB request failed");
+            }
+            final UsbRequest response = mConnection.requestWait();
+            if (response == null) {
+                throw new IOException("Waiting for USB request failed");
+            }
+            nread = buf.position();
+            // Android error propagation is improvable:
+            //   response != null & nread == 0 can be: connection lost, buffer to small, ???
+            if(nread == 0) {
+                testConnection(true);
+            }
+        }
+        return Math.max(nread, 0);
+    }
+
+    @Override
+    public void write(byte[] src, int timeout) throws IOException {write(src, src.length, timeout);}
+
+    @Override
+    public void write(final byte[] src, int length, final int timeout) throws IOException {
+        int offset = 0;
+        long startTime = MonotonicClock.millis();
+        length = Math.min(length, src.length);
+
+        testConnection(false);
+        while (offset < length) {
+            int requestTimeout;
+            final int requestLength;
+            final int actualLength;
+
+            synchronized (mWriteBufferLock) {
+                final byte[] writeBuffer;
+
+                if (mWriteBuffer == null) {
+                    mWriteBuffer = new byte[mWriteEndpoint.getMaxPacketSize()];
+                }
+                requestLength = Math.min(length - offset, mWriteBuffer.length);
+                if (offset == 0) {
+                    writeBuffer = src;
+                } else {
+                    // bulkTransfer does not support offsets, make a copy.
+                    System.arraycopy(src, offset, mWriteBuffer, 0, requestLength);
+                    writeBuffer = mWriteBuffer;
+                }
+                if (timeout == 0 || offset == 0) {
+                    requestTimeout = timeout;
+                } else {
+                    requestTimeout = (int)(startTime + timeout - MonotonicClock.millis());
+                    if(requestTimeout == 0)
+                        requestTimeout = -1;
+                }
+                if (requestTimeout < 0) {
+                    actualLength = -2;
+                } else {
+                    actualLength = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, requestLength, requestTimeout);
+                }
+            }
+            long elapsed = MonotonicClock.millis() - startTime;
+            if (DEBUG) {
+                Log.d(TAG, "Wrote " + actualLength + "/" + requestLength + " offset " + offset + "/" + length + " time " + elapsed + "/" + requestTimeout);
+            }
+            if (actualLength <= 0) {
+                String msg = "Error writing " + requestLength + " bytes at offset " + offset + " of total " + src.length + " after " + elapsed + "msec, rc=" + actualLength;
+                if (timeout != 0) {
+                    // could be buffer full because: writing to fast, stopped by flow control
+                    testConnection(elapsed < timeout, msg);
+                    throw new SerialTimeoutException(msg, offset);
+                } else {
+                    throw new IOException(msg);
+
+                }
+            }
+            offset += actualLength;
+        }
+    }
+
+    @Override
+    public boolean isOpen() {
+        return mUsbRequest != null;
+    }
+
+    @Override
+    public abstract void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException;
+
+    @Override
+    public boolean getCD() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public boolean getCTS() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public boolean getDSR() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public boolean getDTR() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public void setDTR(boolean value) throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public boolean getRI() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public boolean getRTS() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public void setRTS(boolean value) throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public EnumSet<ControlLine> getControlLines() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public EnumSet<ControlLine> getSupportedControlLines() throws IOException { return EnumSet.noneOf(ControlLine.class); }
+
+    @Override
+    public void setFlowControl(FlowControl flowcontrol) throws IOException {
+        if (flowcontrol != FlowControl.NONE)
+            throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public FlowControl getFlowControl() { return mFlowControl; }
+
+    @Override
+    public EnumSet<FlowControl> getSupportedFlowControl() { return EnumSet.of(FlowControl.NONE); }
+
+    @Override
+    public boolean getXON() throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException { throw new UnsupportedOperationException(); }
+
+    @Override
+    public void setBreak(boolean value) throws IOException { throw new UnsupportedOperationException(); }
+
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java

@@ -1,21 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
@@ -23,15 +8,12 @@ package com.hoho.android.usbserial.driver;
 
 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
-import android.hardware.usb.UsbRequest;
-import android.util.Log;
 
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.util.ArrayList;
+import java.util.EnumSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -63,27 +45,32 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
 
     public class Cp21xxSerialPort extends CommonUsbSerialPort {
 
-        private static final int DEFAULT_BAUD_RATE = 9600;
-
         private static final int USB_WRITE_TIMEOUT_MILLIS = 5000;
 
         /*
          * Configuration Request Types
          */
         private static final int REQTYPE_HOST_TO_DEVICE = 0x41;
+        private static final int REQTYPE_DEVICE_TO_HOST = 0xc1;
 
         /*
          * Configuration Request Codes
          */
         private static final int SILABSER_IFC_ENABLE_REQUEST_CODE = 0x00;
-        private static final int SILABSER_SET_BAUDDIV_REQUEST_CODE = 0x01;
         private static final int SILABSER_SET_LINE_CTL_REQUEST_CODE = 0x03;
+        private static final int SILABSER_SET_BREAK_REQUEST_CODE = 0x05;
         private static final int SILABSER_SET_MHS_REQUEST_CODE = 0x07;
-        private static final int SILABSER_SET_BAUDRATE = 0x1E;
+        private static final int SILABSER_GET_MDMSTS_REQUEST_CODE = 0x08;
+        private static final int SILABSER_SET_XON_REQUEST_CODE = 0x09;
+        private static final int SILABSER_SET_XOFF_REQUEST_CODE = 0x0A;
+        private static final int SILABSER_GET_COMM_STATUS_REQUEST_CODE = 0x10;
         private static final int SILABSER_FLUSH_REQUEST_CODE = 0x12;
+        private static final int SILABSER_SET_FLOW_REQUEST_CODE = 0x13;
+        private static final int SILABSER_SET_CHARS_REQUEST_CODE = 0x19;
+        private static final int SILABSER_SET_BAUDRATE_REQUEST_CODE = 0x1E;
 
-       private static final int FLUSH_READ_CODE = 0x0a;
-       private static final int FLUSH_WRITE_CODE = 0x05;
+        private static final int FLUSH_READ_CODE = 0x0a;
+        private static final int FLUSH_WRITE_CODE = 0x05;
 
         /*
          * SILABSER_IFC_ENABLE_REQUEST_CODE
@@ -91,24 +78,27 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
         private static final int UART_ENABLE = 0x0001;
         private static final int UART_DISABLE = 0x0000;
 
-        /*
-         * SILABSER_SET_BAUDDIV_REQUEST_CODE
-         */
-        private static final int BAUD_RATE_GEN_FREQ = 0x384000;
-
         /*
          * SILABSER_SET_MHS_REQUEST_CODE
          */
-        private static final int MCR_DTR = 0x0001;
-        private static final int MCR_RTS = 0x0002;
-        private static final int MCR_ALL = 0x0003;
+        private static final int DTR_ENABLE = 0x101;
+        private static final int DTR_DISABLE = 0x100;
+        private static final int RTS_ENABLE = 0x202;
+        private static final int RTS_DISABLE = 0x200;
 
-        private static final int CONTROL_WRITE_DTR = 0x0100;
-        private static final int CONTROL_WRITE_RTS = 0x0200;
+        /*
+        * SILABSER_GET_MDMSTS_REQUEST_CODE
+         */
+        private static final int STATUS_DTR = 0x01;
+        private static final int STATUS_RTS = 0x02;
+        private static final int STATUS_CTS = 0x10;
+        private static final int STATUS_DSR = 0x20;
+        private static final int STATUS_RI = 0x40;
+        private static final int STATUS_CD = 0x80;
 
-        private UsbEndpoint mReadEndpoint;
-        private UsbEndpoint mWriteEndpoint;
-        private UsbRequest mUsbRequest;
+
+        private boolean dtr = false;
+        private boolean rts = false;
 
         // second port of Cp2105 has limited baudRate, dataBits, stopBits, parity
         // unsupported baudrate returns error at controlTransfer(), other parameters are silently ignored
@@ -123,139 +113,58 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
             return Cp21xxSerialDriver.this;
         }
 
-        private int setConfigSingle(int request, int value) {
-            return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request, value,
+        private void setConfigSingle(int request, int value) throws IOException {
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request, value,
                     mPortNumber, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Control transfer failed: " + request + " / " + value + " -> " + result);
+            }
+        }
+
+        private byte getStatus() throws IOException {
+            byte[] buffer = new byte[1];
+            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, SILABSER_GET_MDMSTS_REQUEST_CODE, 0,
+                    mPortNumber, buffer, buffer.length, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != buffer.length) {
+                throw new IOException("Control transfer failed: " + SILABSER_GET_MDMSTS_REQUEST_CODE + " / " + 0 + " -> " + result);
+            }
+            return buffer[0];
         }
 
         @Override
-        public void open(UsbDeviceConnection connection) throws IOException {
-            if (mConnection != null) {
-                throw new IOException("Already opened.");
-            }
-
-            mConnection = connection;
-            boolean opened = false;
+        protected void openInt() throws IOException {
             mIsRestrictedPort = mDevice.getInterfaceCount() == 2 && mPortNumber == 1;
-            try {
-                if(mPortNumber >= mDevice.getInterfaceCount()) {
-                    throw new IOException("Unknown port number");
-                }
-                UsbInterface dataIface = mDevice.getInterface(mPortNumber);
-                if (!mConnection.claimInterface(dataIface, true)) {
-                    throw new IOException("Could not claim interface " + mPortNumber);
-                }
-                for (int i = 0; i < dataIface.getEndpointCount(); i++) {
-                    UsbEndpoint ep = dataIface.getEndpoint(i);
-                    if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
-                        if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
-                            mReadEndpoint = ep;
-                        } else {
-                            mWriteEndpoint = ep;
-                        }
-                    }
-                }
-
-                setConfigSingle(SILABSER_IFC_ENABLE_REQUEST_CODE, UART_ENABLE);
-                setConfigSingle(SILABSER_SET_MHS_REQUEST_CODE, MCR_ALL | CONTROL_WRITE_DTR | CONTROL_WRITE_RTS);
-                setConfigSingle(SILABSER_SET_BAUDDIV_REQUEST_CODE, BAUD_RATE_GEN_FREQ / DEFAULT_BAUD_RATE);
-    //            setParameters(DEFAULT_BAUD_RATE, DEFAULT_DATA_BITS, DEFAULT_STOP_BITS, DEFAULT_PARITY);
-                opened = true;
-            } finally {
-                if (!opened) {
-                    try {
-                        close();
-                    } catch (IOException e) {
-                        // Ignore IOExceptions during close()
+            if(mPortNumber >= mDevice.getInterfaceCount()) {
+                throw new IOException("Unknown port number");
+            }
+            UsbInterface dataIface = mDevice.getInterface(mPortNumber);
+            if (!mConnection.claimInterface(dataIface, true)) {
+                throw new IOException("Could not claim interface " + mPortNumber);
+            }
+            for (int i = 0; i < dataIface.getEndpointCount(); i++) {
+                UsbEndpoint ep = dataIface.getEndpoint(i);
+                if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
+                    if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
+                        mReadEndpoint = ep;
+                    } else {
+                        mWriteEndpoint = ep;
                     }
                 }
             }
+
+            setConfigSingle(SILABSER_IFC_ENABLE_REQUEST_CODE, UART_ENABLE);
+            setConfigSingle(SILABSER_SET_MHS_REQUEST_CODE, (dtr ? DTR_ENABLE : DTR_DISABLE) | (rts ? RTS_ENABLE : RTS_DISABLE));
+            setFlowControl(mFlowControl);
         }
 
         @Override
-        public void close() throws IOException {
-            if (mConnection == null) {
-                throw new IOException("Already closed");
-            }
-            synchronized (this) {
-                if(mUsbRequest != null) {
-                    mUsbRequest.cancel();
-                }
-            }
+        protected void closeInt() {
             try {
                 setConfigSingle(SILABSER_IFC_ENABLE_REQUEST_CODE, UART_DISABLE);
-            } catch (Exception ignored)
-            {}
+            } catch (Exception ignored) {}
             try {
-                mConnection.close();
-            } finally {
-                mConnection = null;
-            }
-        }
-
-        @Override
-        public int read(byte[] dest, int timeoutMillis) throws IOException {
-            final UsbRequest request = new UsbRequest();
-            try {
-                request.initialize(mConnection, mReadEndpoint);
-                final ByteBuffer buf = ByteBuffer.wrap(dest);
-                if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
-                }
-                mUsbRequest = request;
-                final UsbRequest response = mConnection.requestWait();
-                synchronized (this) {
-                    mUsbRequest = null;
-                }
-                if (response == null) {
-                    throw new IOException("Null response");
-                }
-
-                final int nread = buf.position();
-                if (nread > 0) {
-                    //Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, dest.length)));
-                    return nread;
-                } else {
-                    return 0;
-                }
-            } finally {
-                mUsbRequest = null;
-                request.close();
-            }
-        }
-
-        @Override
-        public int write(byte[] src, int timeoutMillis) throws IOException {
-            int offset = 0;
-
-            while (offset < src.length) {
-                final int writeLength;
-                final int amtWritten;
-
-                synchronized (mWriteBufferLock) {
-                    final byte[] writeBuffer;
-
-                    writeLength = Math.min(src.length - offset, mWriteBuffer.length);
-                    if (offset == 0) {
-                        writeBuffer = src;
-                    } else {
-                        // bulkTransfer does not support offsets, make a copy.
-                        System.arraycopy(src, offset, mWriteBuffer, 0, writeLength);
-                        writeBuffer = mWriteBuffer;
-                    }
-
-                    amtWritten = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, writeLength,
-                            timeoutMillis);
-                }
-                if (amtWritten <= 0) {
-                    throw new IOException("Error writing " + writeLength
-                            + " bytes at offset " + offset + " length=" + src.length);
-                }
-
-                Log.d(TAG, "Wrote amt=" + amtWritten + " attempted=" + writeLength);
-                offset += amtWritten;
-            }
-            return offset;
+                mConnection.releaseInterface(mDevice.getInterface(mPortNumber));
+            } catch(Exception ignored) {}
         }
 
         private void setBaudRate(int baudRate) throws IOException {
@@ -265,40 +174,42 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
                     (byte) ((baudRate >> 16) & 0xff),
                     (byte) ((baudRate >> 24) & 0xff)
             };
-            int ret = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SILABSER_SET_BAUDRATE,
+            int ret = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SILABSER_SET_BAUDRATE_REQUEST_CODE,
                     0, mPortNumber, data, 4, USB_WRITE_TIMEOUT_MILLIS);
             if (ret < 0) {
-                throw new IOException("Error setting baud rate.");
+                throw new IOException("Error setting baud rate");
             }
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
-                throws IOException {
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
             setBaudRate(baudRate);
 
             int configDataBits = 0;
             switch (dataBits) {
                 case DATABITS_5:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0500;
                     break;
                 case DATABITS_6:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0600;
                     break;
                 case DATABITS_7:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0700;
                     break;
                 case DATABITS_8:
                     configDataBits |= 0x0800;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
             }
             
             switch (parity) {
@@ -312,95 +223,188 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
                     break;
                 case PARITY_MARK:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported parity value: mark");
+                        throw new UnsupportedOperationException("Unsupported parity: mark");
                     configDataBits |= 0x0030;
                     break;
                 case PARITY_SPACE:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported parity value: space");
+                        throw new UnsupportedOperationException("Unsupported parity: space");
                     configDataBits |= 0x0040;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown parity value: " + parity);
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
             }
             
             switch (stopBits) {
                 case STOPBITS_1:
                     break;
                 case STOPBITS_1_5:
-                    throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
                 case STOPBITS_2:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported stopBits value: 2");
+                        throw new UnsupportedOperationException("Unsupported stop bits: 2");
                     configDataBits |= 2;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
             setConfigSingle(SILABSER_SET_LINE_CTL_REQUEST_CODE, configDataBits);
         }
 
         @Override
         public boolean getCD() throws IOException {
-            return false;
+            return (getStatus() & STATUS_CD) != 0;
         }
 
         @Override
         public boolean getCTS() throws IOException {
-            return false;
+            return (getStatus() & STATUS_CTS) != 0;
         }
 
         @Override
         public boolean getDSR() throws IOException {
-            return false;
+            return (getStatus() & STATUS_DSR) != 0;
         }
 
         @Override
         public boolean getDTR() throws IOException {
-            return true;
+            return dtr;
         }
 
         @Override
         public void setDTR(boolean value) throws IOException {
+            dtr = value;
+            setConfigSingle(SILABSER_SET_MHS_REQUEST_CODE, dtr ? DTR_ENABLE : DTR_DISABLE);
         }
 
         @Override
         public boolean getRI() throws IOException {
-            return false;
+            return (getStatus() & STATUS_RI) != 0;
         }
 
         @Override
         public boolean getRTS() throws IOException {
-            return true;
+            return rts;
         }
 
         @Override
         public void setRTS(boolean value) throws IOException {
+            rts = value;
+            setConfigSingle(SILABSER_SET_MHS_REQUEST_CODE, rts ? RTS_ENABLE : RTS_DISABLE);
         }
 
         @Override
-        public boolean purgeHwBuffers(boolean purgeReadBuffers,
-                boolean purgeWriteBuffers) throws IOException {
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            byte status = getStatus();
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            //if(rts) set.add(ControlLine.RTS);                      // configured value
+            if((status & STATUS_RTS) != 0) set.add(ControlLine.RTS); // actual value
+            if((status & STATUS_CTS) != 0) set.add(ControlLine.CTS);
+            //if(dtr) set.add(ControlLine.DTR);                      // configured value
+            if((status & STATUS_DTR) != 0) set.add(ControlLine.DTR); // actual value
+            if((status & STATUS_DSR) != 0) set.add(ControlLine.DSR);
+            if((status & STATUS_CD) != 0) set.add(ControlLine.CD);
+            if((status & STATUS_RI) != 0) set.add(ControlLine.RI);
+            return set;
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.allOf(ControlLine.class);
+        }
+
+        @Override
+        public boolean getXON() throws IOException {
+            byte[] buffer = new byte[0x13];
+            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, SILABSER_GET_COMM_STATUS_REQUEST_CODE, 0,
+                    mPortNumber, buffer, buffer.length, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != buffer.length) {
+                throw new IOException("Control transfer failed: " + SILABSER_GET_COMM_STATUS_REQUEST_CODE + " -> " + result);
+            }
+            return (buffer[4] & 8) == 0;
+        }
+
+        /**
+         * emulate external XON/OFF
+         * @throws IOException
+         */
+        public void setXON(boolean value) throws IOException {
+            setConfigSingle(value ? SILABSER_SET_XON_REQUEST_CODE : SILABSER_SET_XOFF_REQUEST_CODE, 0);
+        }
+
+        @Override
+        public void setFlowControl(FlowControl flowControl) throws IOException {
+            byte[] data = new byte[16];
+            if(flowControl == FlowControl.RTS_CTS) {
+                data[4] |=  0b1000_0000; // RTS
+                data[0] |=  0b0000_1000; // CTS
+            } else {
+                if(rts)
+                    data[4] |= 0b0100_0000;
+            }
+            if(flowControl == FlowControl.DTR_DSR) {
+                data[0] |= 0b0000_0010; // DTR
+                data[0] |= 0b0001_0000; // DSR
+            } else {
+                if(dtr)
+                    data[0] |= 0b0000_0001;
+            }
+            if(flowControl == FlowControl.XON_XOFF) {
+                byte[] chars = new byte[]{0, 0, 0, 0, CHAR_XON, CHAR_XOFF};
+                int ret = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SILABSER_SET_CHARS_REQUEST_CODE,
+                        0, mPortNumber, chars, chars.length, USB_WRITE_TIMEOUT_MILLIS);
+                if (ret != chars.length) {
+                    throw new IOException("Error setting XON/XOFF chars");
+                }
+                data[4] |= 0b0000_0011;
+                data[7] |= 0b1000_0000;
+                data[8] = (byte)128;
+                data[12] = (byte)128;
+            }
+            if(flowControl == FlowControl.XON_XOFF_INLINE) {
+                throw new UnsupportedOperationException();
+            }
+            int ret = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SILABSER_SET_FLOW_REQUEST_CODE,
+                    0, mPortNumber, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
+            if (ret != data.length) {
+                throw new IOException("Error setting flow control");
+            }
+            if(flowControl == FlowControl.XON_XOFF) {
+                setXON(true);
+            }
+            mFlowControl = flowControl;
+        }
+
+        @Override
+        public EnumSet<FlowControl> getSupportedFlowControl() {
+            return EnumSet.of(FlowControl.NONE, FlowControl.RTS_CTS, FlowControl.DTR_DSR, FlowControl.XON_XOFF);
+        }
+
+        @Override
+        // note: only working on some devices, on other devices ignored w/o error
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
             int value = (purgeReadBuffers ? FLUSH_READ_CODE : 0)
                     | (purgeWriteBuffers ? FLUSH_WRITE_CODE : 0);
 
             if (value != 0) {
                 setConfigSingle(SILABSER_FLUSH_REQUEST_CODE, value);
             }
-
-            return true;
         }
 
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            setConfigSingle(SILABSER_SET_BREAK_REQUEST_CODE, value ? 1 : 0);
+        }
     }
 
+    @SuppressWarnings({"unused"})
     public static Map<Integer, int[]> getSupportedDevices() {
-        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<Integer, int[]>();
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_SILABS),
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_SILABS,
                 new int[] {
-            UsbId.SILABS_CP2102,
+            UsbId.SILABS_CP2102, // same ID for CP2101, CP2103, CP2104, CP2109
             UsbId.SILABS_CP2105,
             UsbId.SILABS_CP2108,
-            UsbId.SILABS_CP2110
         });
         return supportedDevices;
     }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java

@@ -1,20 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
+ * Copyright 2020 kai morich <mail@kai-morich.de>
  *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
@@ -23,85 +9,33 @@ package com.hoho.android.usbserial.driver;
 
 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
-import android.hardware.usb.UsbEndpoint;
-import android.hardware.usb.UsbRequest;
 import android.util.Log;
 
+import com.hoho.android.usbserial.util.MonotonicClock;
+
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.util.ArrayList;
+import java.util.EnumSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-/**
- * A {@link CommonUsbSerialPort} implementation for a variety of FTDI devices
- * <p>
- * This driver is based on <a
- * href="http://www.intra2net.com/en/developer/libftdi">libftdi</a>, and is
- * copyright and subject to the following terms:
+/*
+ * driver is implemented from various information scattered over FTDI documentation
  *
- * <pre>
- *   Copyright (C) 2003 by Intra2net AG
+ * baud rate calculation https://www.ftdichip.com/Support/Documents/AppNotes/AN232B-05_BaudRates.pdf
+ * control bits https://www.ftdichip.com/Firmware/Precompiled/UM_VinculumFirmware_V205.pdf
+ * device type https://www.ftdichip.com/Support/Documents/AppNotes/AN_233_Java_D2XX_for_Android_API_User_Manual.pdf -> bvdDevice
  *
- *   This program is free software; you can redistribute it and/or modify
- *   it under the terms of the GNU Lesser General Public License
- *   version 2.1 as published by the Free Software Foundation;
- *
- *   opensource@intra2net.com
- *   http://www.intra2net.com/en/developer/libftdi
- * </pre>
- *
- * </p>
- * <p>
- * Some FTDI devices have not been tested; see later listing of supported and
- * unsupported devices. Devices listed as "supported" support the following
- * features:
- * <ul>
- * <li>Read and write of serial data (see
- * {@link CommonUsbSerialPort#read(byte[], int)} and
- * {@link CommonUsbSerialPort#write(byte[], int)}.</li>
- * <li>Setting serial line parameters (see
- * {@link CommonUsbSerialPort#setParameters(int, int, int, int)}.</li>
- * </ul>
- * </p>
- * <p>
- * Supported and tested devices:
- * <ul>
- * <li>{@value DeviceType#TYPE_R}</li>
- * <li>{@value DeviceType#TYPE_2232H}</li>
- * <li>{@value DeviceType#TYPE_4232H}</li>
- * </ul>
- * </p>
- * <p>
- * Unsupported but possibly working devices (please contact the author with
- * feedback or patches):
- * <ul>
- * <li>{@value DeviceType#TYPE_2232C}</li>
- * <li>{@value DeviceType#TYPE_AM}</li>
- * <li>{@value DeviceType#TYPE_BM}</li>
- * </ul>
- * </p>
- *
- * @author mike wakerly (opensource@hoho.com)
- * @see <a href="https://github.com/mik3y/usb-serial-for-android">USB Serial
- *      for Android project page</a>
- * @see <a href="http://www.ftdichip.com/">FTDI Homepage</a>
- * @see <a href="http://www.intra2net.com/en/developer/libftdi">libftdi</a>
  */
+
 public class FtdiSerialDriver implements UsbSerialDriver {
 
+    private static final String TAG = FtdiSerialPort.class.getSimpleName();
+
     private final UsbDevice mDevice;
     private final List<UsbSerialPort> mPorts;
 
-    /**
-     * FTDI chip types.
-     */
-    private static enum DeviceType {
-        TYPE_BM, TYPE_AM, TYPE_2232C, TYPE_R, TYPE_2232H, TYPE_4232H;
-    }
-
     public FtdiSerialDriver(UsbDevice device) {
         mDevice = device;
         mPorts = new ArrayList<>();
@@ -120,70 +54,39 @@ public class FtdiSerialDriver implements UsbSerialDriver {
         return mPorts;
     }
 
-    private class FtdiSerialPort extends CommonUsbSerialPort {
+    public class FtdiSerialPort extends CommonUsbSerialPort {
 
-        public static final int USB_TYPE_STANDARD = 0x00 << 5;
-        public static final int USB_TYPE_CLASS = 0x00 << 5;
-        public static final int USB_TYPE_VENDOR = 0x00 << 5;
-        public static final int USB_TYPE_RESERVED = 0x00 << 5;
+        private static final int USB_WRITE_TIMEOUT_MILLIS = 5000;
+        private static final int READ_HEADER_LENGTH = 2; // contains MODEM_STATUS
 
-        public static final int USB_RECIP_DEVICE = 0x00;
-        public static final int USB_RECIP_INTERFACE = 0x01;
-        public static final int USB_RECIP_ENDPOINT = 0x02;
-        public static final int USB_RECIP_OTHER = 0x03;
+        private static final int REQTYPE_HOST_TO_DEVICE = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_OUT;
+        private static final int REQTYPE_DEVICE_TO_HOST = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_IN;
 
-        public static final int USB_ENDPOINT_IN = 0x80;
-        public static final int USB_ENDPOINT_OUT = 0x00;
+        private static final int RESET_REQUEST = 0;
+        private static final int MODEM_CONTROL_REQUEST = 1;
+        private static final int SET_FLOW_CONTROL_REQUEST = 2;
+        private static final int SET_BAUD_RATE_REQUEST = 3;
+        private static final int SET_DATA_REQUEST = 4;
+        private static final int GET_MODEM_STATUS_REQUEST = 5;
+        private static final int SET_LATENCY_TIMER_REQUEST = 9;
+        private static final int GET_LATENCY_TIMER_REQUEST = 10;
 
-        public static final int USB_WRITE_TIMEOUT_MILLIS = 5000;
-        public static final int USB_READ_TIMEOUT_MILLIS = 5000;
+        private static final int MODEM_CONTROL_DTR_ENABLE = 0x0101;
+        private static final int MODEM_CONTROL_DTR_DISABLE = 0x0100;
+        private static final int MODEM_CONTROL_RTS_ENABLE = 0x0202;
+        private static final int MODEM_CONTROL_RTS_DISABLE = 0x0200;
+        private static final int MODEM_STATUS_CTS = 0x10;
+        private static final int MODEM_STATUS_DSR = 0x20;
+        private static final int MODEM_STATUS_RI = 0x40;
+        private static final int MODEM_STATUS_CD = 0x80;
+        private static final int RESET_ALL = 0;
+        private static final int RESET_PURGE_RX = 1;
+        private static final int RESET_PURGE_TX = 2;
 
-        // From ftdi.h
-        /**
-         * Reset the port.
-         */
-        private static final int SIO_RESET_REQUEST = 0;
-
-        /**
-         * Set the modem control register.
-         */
-        private static final int SIO_MODEM_CTRL_REQUEST = 1;
-
-        /**
-         * Set flow control register.
-         */
-        private static final int SIO_SET_FLOW_CTRL_REQUEST = 2;
-
-        /**
-         * Set baud rate.
-         */
-        private static final int SIO_SET_BAUD_RATE_REQUEST = 3;
-
-        /**
-         * Set the data characteristics of the port.
-         */
-        private static final int SIO_SET_DATA_REQUEST = 4;
-
-        private static final int SIO_RESET_SIO = 0;
-        private static final int SIO_RESET_PURGE_RX = 1;
-        private static final int SIO_RESET_PURGE_TX = 2;
-
-        public static final int FTDI_DEVICE_OUT_REQTYPE =
-                UsbConstants.USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_OUT;
-
-        public static final int FTDI_DEVICE_IN_REQTYPE =
-                UsbConstants.USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN;
-
-        /**
-         * Length of the modem status header, transmitted with every read.
-         */
-        private static final int MODEM_STATUS_HEADER_LENGTH = 2;
-
-        private final String TAG = FtdiSerialDriver.class.getSimpleName();
-
-        private DeviceType mType;
-
-        private int mIndex = 0;
+        private boolean baudRateWithPort = false;
+        private boolean dtr = false;
+        private boolean rts = false;
+        private int breakConfig = 0;
 
         public FtdiSerialPort(UsbDevice device, int portNumber) {
             super(device, portNumber);
@@ -194,375 +97,380 @@ public class FtdiSerialDriver implements UsbSerialDriver {
             return FtdiSerialDriver.this;
         }
 
-        /**
-         * Filter FTDI status bytes from buffer
-         * @param src The source buffer (which contains status bytes)
-         * @param dest The destination buffer to write the status bytes into (can be src)
-         * @param totalBytesRead Number of bytes read to src
-         * @param maxPacketSize The USB endpoint max packet size
-         * @return The number of payload bytes
-         */
-        private final int filterStatusBytes(byte[] src, byte[] dest, int totalBytesRead, int maxPacketSize) {
-            final int packetsCount = (totalBytesRead + maxPacketSize -1 )/ maxPacketSize;
-            for (int packetIdx = 0; packetIdx < packetsCount; ++packetIdx) {
-                final int count = (packetIdx == (packetsCount - 1))
-                        ? totalBytesRead - packetIdx * maxPacketSize - MODEM_STATUS_HEADER_LENGTH
-                        : maxPacketSize - MODEM_STATUS_HEADER_LENGTH;
-                if (count > 0) {
-                    System.arraycopy(src,
-                            packetIdx * maxPacketSize + MODEM_STATUS_HEADER_LENGTH,
-                            dest,
-                            packetIdx * (maxPacketSize - MODEM_STATUS_HEADER_LENGTH),
-                            count);
-                }
+
+        @Override
+        protected void openInt() throws IOException {
+            if (!mConnection.claimInterface(mDevice.getInterface(mPortNumber), true)) {
+                throw new IOException("Could not claim interface " + mPortNumber);
             }
-
-          return totalBytesRead - (packetsCount * 2);
-        }
-
-        public void reset() throws IOException {
-            // TODO(mikey): autodetect.
-            mType = DeviceType.TYPE_R;
-            if(mDevice.getInterfaceCount() > 1) {
-                mIndex = mPortNumber + 1;
-                if (mDevice.getInterfaceCount() == 2)
-                    mType = DeviceType.TYPE_2232H;
-                if (mDevice.getInterfaceCount() == 4)
-                    mType = DeviceType.TYPE_4232H;
+            if (mDevice.getInterface(mPortNumber).getEndpointCount() < 2) {
+                throw new IOException("Not enough endpoints");
             }
+            mReadEndpoint = mDevice.getInterface(mPortNumber).getEndpoint(0);
+            mWriteEndpoint = mDevice.getInterface(mPortNumber).getEndpoint(1);
 
-            int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE, SIO_RESET_REQUEST,
-                    SIO_RESET_SIO, mIndex, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, RESET_REQUEST,
+                    RESET_ALL, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
             if (result != 0) {
                 throw new IOException("Reset failed: result=" + result);
             }
+            result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, MODEM_CONTROL_REQUEST,
+                    (dtr ? MODEM_CONTROL_DTR_ENABLE : MODEM_CONTROL_DTR_DISABLE) |
+                            (rts ? MODEM_CONTROL_RTS_ENABLE : MODEM_CONTROL_RTS_DISABLE),
+                    mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Init RTS,DTR failed: result=" + result);
+            }
+            setFlowControl(mFlowControl);
+
+            // mDevice.getVersion() would require API 23
+            byte[] rawDescriptors = mConnection.getRawDescriptors();
+            if(rawDescriptors == null || rawDescriptors.length < 14) {
+                throw new IOException("Could not get device descriptors");
+            }
+            int deviceType = rawDescriptors[13];
+            baudRateWithPort = deviceType == 7 || deviceType == 8 || deviceType == 9 // ...H devices
+                    || mDevice.getInterfaceCount() > 1; // FT2232C
         }
 
         @Override
-        public void open(UsbDeviceConnection connection) throws IOException {
-            if (mConnection != null) {
-                throw new IOException("Already open");
-            }
-            mConnection = connection;
-
-            boolean opened = false;
+        protected void closeInt() {
             try {
-                if (connection.claimInterface(mDevice.getInterface(mPortNumber), true)) {
-                    Log.d(TAG, "claimInterface " + mPortNumber + " SUCCESS");
-                } else {
-                    throw new IOException("Error claiming interface " + mPortNumber);
-                }
-                reset();
-                opened = true;
-            } finally {
-                if (!opened) {
-                    close();
-                    mConnection = null;
-                }
-            }
+                mConnection.releaseInterface(mDevice.getInterface(mPortNumber));
+            } catch(Exception ignored) {}
         }
 
         @Override
-        public void close() throws IOException {
-            if (mConnection == null) {
-                throw new IOException("Already closed");
-            }
-            try {
-                mConnection.close();
-            } finally {
-                mConnection = null;
+        public int read(final byte[] dest, final int timeout) throws IOException
+        {
+            if(dest.length <= READ_HEADER_LENGTH) {
+                throw new IllegalArgumentException("Read buffer too small");
+                // could allocate larger buffer, including space for 2 header bytes, but this would
+                // result in buffers not being 64 byte aligned any more, causing data loss at continuous
+                // data transfer at high baud rates when buffers are fully filled.
             }
+            return read(dest, dest.length, timeout);
         }
 
         @Override
-        public int read(byte[] dest, int timeoutMillis) throws IOException {
-            final UsbEndpoint endpoint = mDevice.getInterface(mPortNumber).getEndpoint(0);
-            final UsbRequest request = new UsbRequest();
-            final ByteBuffer buf = ByteBuffer.wrap(dest);
-            try {
-                request.initialize(mConnection, endpoint);
-                if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
-                }
-
-                final UsbRequest response = mConnection.requestWait();
-                if (response == null) {
-                    throw new IOException("Null response");
-                }
-            } finally {
-                request.close();
+        public int read(final byte[] dest, int length, final int timeout) throws IOException {
+            if(length <= READ_HEADER_LENGTH) {
+                throw new IllegalArgumentException("Read length too small");
+                // could allocate larger buffer, including space for 2 header bytes, but this would
+                // result in buffers not being 64 byte aligned any more, causing data loss at continuous
+                // data transfer at high baud rates when buffers are fully filled.
             }
-
-            final int totalBytesRead = buf.position();
-            if (totalBytesRead < MODEM_STATUS_HEADER_LENGTH) {
-                throw new IOException("Expected at least " + MODEM_STATUS_HEADER_LENGTH + " bytes");
+            length = Math.min(length, dest.length);
+            int nread;
+            if (timeout != 0) {
+                long endTime = MonotonicClock.millis() + timeout;
+                do {
+                    nread = super.read(dest, length, Math.max(1, (int)(endTime - MonotonicClock.millis())), false);
+                } while (nread == READ_HEADER_LENGTH && MonotonicClock.millis() < endTime);
+                if(nread <= 0)
+                    testConnection(MonotonicClock.millis() < endTime);
+            } else {
+                do {
+                    nread = super.read(dest, length, timeout);
+                } while (nread == READ_HEADER_LENGTH);
             }
-
-            return filterStatusBytes(dest, dest, totalBytesRead, endpoint.getMaxPacketSize());
+            return readFilter(dest, nread);
         }
 
-        @Override
-        public int write(byte[] src, int timeoutMillis) throws IOException {
-            final UsbEndpoint endpoint = mDevice.getInterface(mPortNumber).getEndpoint(1);
-            int offset = 0;
-
-            while (offset < src.length) {
-                final int writeLength;
-                final int amtWritten;
-
-                synchronized (mWriteBufferLock) {
-                    final byte[] writeBuffer;
-
-                    writeLength = Math.min(src.length - offset, mWriteBuffer.length);
-                    if (offset == 0) {
-                        writeBuffer = src;
-                    } else {
-                        // bulkTransfer does not support offsets, make a copy.
-                        System.arraycopy(src, offset, mWriteBuffer, 0, writeLength);
-                        writeBuffer = mWriteBuffer;
-                    }
-
-                    amtWritten = mConnection.bulkTransfer(endpoint, writeBuffer, writeLength,
-                            timeoutMillis);
-                }
-
-                if (amtWritten <= 0) {
-                    throw new IOException("Error writing " + writeLength
-                            + " bytes at offset " + offset + " length=" + src.length);
-                }
-
-                Log.d(TAG, "Wrote amtWritten=" + amtWritten + " attempted=" + writeLength);
-                offset += amtWritten;
+        protected int readFilter(byte[] buffer, int totalBytesRead) throws IOException {
+            final int maxPacketSize = mReadEndpoint.getMaxPacketSize();
+            int destPos = 0;
+            for(int srcPos = 0; srcPos < totalBytesRead; srcPos += maxPacketSize) {
+                int length = Math.min(srcPos + maxPacketSize, totalBytesRead) - (srcPos + READ_HEADER_LENGTH);
+                if (length < 0)
+                    throw new IOException("Expected at least " + READ_HEADER_LENGTH + " bytes");
+                System.arraycopy(buffer, srcPos + READ_HEADER_LENGTH, buffer, destPos, length);
+                destPos += length;
             }
-            return offset;
+            //Log.d(TAG, "read filter " + totalBytesRead + " -> " + destPos);
+            return destPos;
         }
 
-        private int setBaudRate(int baudRate) throws IOException {
-            long[] vals = convertBaudrate(baudRate);
-            long actualBaudrate = vals[0];
-            long index = vals[1];
-            long value = vals[2];
-            int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE,
-                    SIO_SET_BAUD_RATE_REQUEST, (int) value, (int) index,
-                    null, 0, USB_WRITE_TIMEOUT_MILLIS);
+        private void setBaudrate(int baudRate) throws IOException {
+            int divisor, subdivisor, effectiveBaudRate;
+            if (baudRate > 3500000) {
+                throw new UnsupportedOperationException("Baud rate to high");
+            } else if(baudRate >= 2500000) {
+                divisor = 0;
+                subdivisor = 0;
+                effectiveBaudRate = 3000000;
+            } else if(baudRate >= 1750000) {
+                divisor = 1;
+                subdivisor = 0;
+                effectiveBaudRate = 2000000;
+            } else {
+                divisor = (24000000 << 1) / baudRate;
+                divisor = (divisor + 1) >> 1; // round
+                subdivisor = divisor & 0x07;
+                divisor >>= 3;
+                if (divisor > 0x3fff) // exceeds bit 13 at 183 baud
+                    throw new UnsupportedOperationException("Baud rate to low");
+                effectiveBaudRate = (24000000 << 1) / ((divisor << 3) + subdivisor);
+                effectiveBaudRate = (effectiveBaudRate +1) >> 1;
+            }
+            double baudRateError = Math.abs(1.0 - (effectiveBaudRate / (double)baudRate));
+            if(baudRateError >= 0.031) // can happen only > 1.5Mbaud
+                throw new UnsupportedOperationException(String.format("Baud rate deviation %.1f%% is higher than allowed 3%%", baudRateError*100));
+            int value = divisor;
+            int index = 0;
+            switch(subdivisor) {
+                case 0:                              break; // 16,15,14 = 000 - sub-integer divisor = 0
+                case 4: value |= 0x4000;             break; // 16,15,14 = 001 - sub-integer divisor = 0.5
+                case 2: value |= 0x8000;             break; // 16,15,14 = 010 - sub-integer divisor = 0.25
+                case 1: value |= 0xc000;             break; // 16,15,14 = 011 - sub-integer divisor = 0.125
+                case 3: value |= 0x0000; index |= 1; break; // 16,15,14 = 100 - sub-integer divisor = 0.375
+                case 5: value |= 0x4000; index |= 1; break; // 16,15,14 = 101 - sub-integer divisor = 0.625
+                case 6: value |= 0x8000; index |= 1; break; // 16,15,14 = 110 - sub-integer divisor = 0.75
+                case 7: value |= 0xc000; index |= 1; break; // 16,15,14 = 111 - sub-integer divisor = 0.875
+            }
+            if(baudRateWithPort) {
+                index <<= 8;
+                index |= mPortNumber+1;
+            }
+            Log.d(TAG, String.format("baud rate=%d, effective=%d, error=%.1f%%, value=0x%04x, index=0x%04x, divisor=%d, subdivisor=%d",
+                    baudRate, effectiveBaudRate, baudRateError*100, value, index, divisor, subdivisor));
+
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SET_BAUD_RATE_REQUEST,
+                    value, index, null, 0, USB_WRITE_TIMEOUT_MILLIS);
             if (result != 0) {
                 throw new IOException("Setting baudrate failed: result=" + result);
             }
-            return (int) actualBaudrate;
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
-                throws IOException {
-            setBaudRate(baudRate);
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            setBaudrate(baudRate);
 
             int config = 0;
             switch (dataBits) {
                 case DATABITS_5:
                 case DATABITS_6:
-                    throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                    throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                 case DATABITS_7:
                 case DATABITS_8:
                     config |= dataBits;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
             }
 
             switch (parity) {
                 case PARITY_NONE:
-                    config |= (0x00 << 8);
                     break;
                 case PARITY_ODD:
-                    config |= (0x01 << 8);
+                    config |= 0x100;
                     break;
                 case PARITY_EVEN:
-                    config |= (0x02 << 8);
+                    config |= 0x200;
                     break;
                 case PARITY_MARK:
-                    config |= (0x03 << 8);
+                    config |= 0x300;
                     break;
                 case PARITY_SPACE:
-                    config |= (0x04 << 8);
+                    config |= 0x400;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown parity value: " + parity);
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
             }
 
             switch (stopBits) {
                 case STOPBITS_1:
-                    config |= (0x00 << 11);
                     break;
                 case STOPBITS_1_5:
-                    throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
                 case STOPBITS_2:
-                    config |= (0x02 << 11);
+                    config |= 0x1000;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
 
-            int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE,
-                    SIO_SET_DATA_REQUEST, config, mIndex,
-                    null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SET_DATA_REQUEST,
+                    config, mPortNumber+1,null, 0, USB_WRITE_TIMEOUT_MILLIS);
             if (result != 0) {
                 throw new IOException("Setting parameters failed: result=" + result);
             }
+            breakConfig = config;
         }
 
-        private long[] convertBaudrate(int baudrate) {
-            // TODO(mikey): Braindead transcription of libfti method.  Clean up,
-            // using more idiomatic Java where possible.
-            int divisor = 24000000 / baudrate;
-            int bestDivisor = 0;
-            int bestBaud = 0;
-            int bestBaudDiff = 0;
-            int fracCode[] = {
-                    0, 3, 2, 4, 1, 5, 6, 7
-            };
-
-            for (int i = 0; i < 2; i++) {
-                int tryDivisor = divisor + i;
-                int baudEstimate;
-                int baudDiff;
-
-                if (tryDivisor <= 8) {
-                    // Round up to minimum supported divisor
-                    tryDivisor = 8;
-                } else if (mType != DeviceType.TYPE_AM && tryDivisor < 12) {
-                    // BM doesn't support divisors 9 through 11 inclusive
-                    tryDivisor = 12;
-                } else if (divisor < 16) {
-                    // AM doesn't support divisors 9 through 15 inclusive
-                    tryDivisor = 16;
-                } else {
-                    if (mType == DeviceType.TYPE_AM) {
-                        // TODO
-                    } else {
-                        if (tryDivisor > 0x1FFFF) {
-                            // Round down to maximum supported divisor value (for
-                            // BM)
-                            tryDivisor = 0x1FFFF;
-                        }
-                    }
-                }
-
-                // Get estimated baud rate (to nearest integer)
-                baudEstimate = (24000000 + (tryDivisor / 2)) / tryDivisor;
-
-                // Get absolute difference from requested baud rate
-                if (baudEstimate < baudrate) {
-                    baudDiff = baudrate - baudEstimate;
-                } else {
-                    baudDiff = baudEstimate - baudrate;
-                }
-
-                if (i == 0 || baudDiff < bestBaudDiff) {
-                    // Closest to requested baud rate so far
-                    bestDivisor = tryDivisor;
-                    bestBaud = baudEstimate;
-                    bestBaudDiff = baudDiff;
-                    if (baudDiff == 0) {
-                        // Spot on! No point trying
-                        break;
-                    }
-                }
+        private int getStatus() throws IOException {
+            byte[] data = new byte[2];
+            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_MODEM_STATUS_REQUEST,
+                    0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != data.length) {
+                throw new IOException("Get modem status failed: result=" + result);
             }
-
-            // Encode the best divisor value
-            long encodedDivisor = (bestDivisor >> 3) | (fracCode[bestDivisor & 7] << 14);
-            // Deal with special cases for encoded value
-            if (encodedDivisor == 1) {
-                encodedDivisor = 0; // 3000000 baud
-            } else if (encodedDivisor == 0x4001) {
-                encodedDivisor = 1; // 2000000 baud (BM only)
-            }
-
-            // Split into "value" and "index" values
-            long value = encodedDivisor & 0xFFFF;
-            long index;
-            if (mType == DeviceType.TYPE_2232C || mType == DeviceType.TYPE_2232H
-                    || mType == DeviceType.TYPE_4232H) {
-                index = (encodedDivisor >> 8) & 0xff00;
-                index |= mIndex;
-            } else {
-                index = (encodedDivisor >> 16) & 0xffff;
-            }
-
-            // Return the nearest baud rate
-            return new long[] {
-                    bestBaud, index, value
-            };
+            return data[0];
         }
 
         @Override
         public boolean getCD() throws IOException {
-            return false;
+            return (getStatus() & MODEM_STATUS_CD) != 0;
         }
 
         @Override
         public boolean getCTS() throws IOException {
-            return false;
+            return (getStatus() & MODEM_STATUS_CTS) != 0;
         }
 
         @Override
         public boolean getDSR() throws IOException {
-            return false;
+            return (getStatus() & MODEM_STATUS_DSR) != 0;
         }
 
         @Override
         public boolean getDTR() throws IOException {
-            return false;
+            return dtr;
         }
 
         @Override
         public void setDTR(boolean value) throws IOException {
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, MODEM_CONTROL_REQUEST,
+                    value ? MODEM_CONTROL_DTR_ENABLE : MODEM_CONTROL_DTR_DISABLE, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Set DTR failed: result=" + result);
+            }
+            dtr = value;
         }
 
         @Override
         public boolean getRI() throws IOException {
-            return false;
+            return (getStatus() & MODEM_STATUS_RI) != 0;
         }
 
         @Override
         public boolean getRTS() throws IOException {
-            return false;
+            return rts;
         }
 
         @Override
         public void setRTS(boolean value) throws IOException {
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, MODEM_CONTROL_REQUEST,
+                    value ? MODEM_CONTROL_RTS_ENABLE : MODEM_CONTROL_RTS_DISABLE, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Set DTR failed: result=" + result);
+            }
+            rts = value;
         }
 
         @Override
-        public boolean purgeHwBuffers(boolean purgeReadBuffers, boolean purgeWriteBuffers) throws IOException {
-            if (purgeReadBuffers) {
-                int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE, SIO_RESET_REQUEST,
-                        SIO_RESET_PURGE_RX, mIndex, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            int status = getStatus();
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            if(rts) set.add(ControlLine.RTS);
+            if((status & MODEM_STATUS_CTS) != 0) set.add(ControlLine.CTS);
+            if(dtr) set.add(ControlLine.DTR);
+            if((status & MODEM_STATUS_DSR) != 0) set.add(ControlLine.DSR);
+            if((status & MODEM_STATUS_CD) != 0) set.add(ControlLine.CD);
+            if((status & MODEM_STATUS_RI) != 0) set.add(ControlLine.RI);
+            return set;
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.allOf(ControlLine.class);
+        }
+
+        @Override
+        public void setFlowControl(FlowControl flowControl) throws IOException {
+            int value = 0;
+            int index = mPortNumber+1;
+            switch (flowControl) {
+                case NONE:
+                    break;
+                case RTS_CTS:
+                    index |= 0x100;
+                    break;
+                case DTR_DSR:
+                    index |= 0x200;
+                    break;
+                case XON_XOFF_INLINE:
+                    value = CHAR_XON + (CHAR_XOFF << 8);
+                    index |= 0x400;
+                    break;
+                default:
+                    throw new UnsupportedOperationException();
+            }
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SET_FLOW_CONTROL_REQUEST,
+                    value, index, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0)
+                throw new IOException("Set flow control failed: result=" + result);
+            mFlowControl = flowControl;
+        }
+
+        @Override
+        public EnumSet<FlowControl> getSupportedFlowControl() {
+            return EnumSet.of(FlowControl.NONE, FlowControl.RTS_CTS, FlowControl.DTR_DSR, FlowControl.XON_XOFF_INLINE);
+        }
+
+        @Override
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+            if (purgeWriteBuffers) {
+                int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, RESET_REQUEST,
+                        RESET_PURGE_RX, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
                 if (result != 0) {
-                    throw new IOException("Flushing RX failed: result=" + result);
+                    throw new IOException("Purge write buffer failed: result=" + result);
                 }
             }
 
-            if (purgeWriteBuffers) {
-                int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE, SIO_RESET_REQUEST,
-                        SIO_RESET_PURGE_TX, mIndex, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (purgeReadBuffers) {
+                int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, RESET_REQUEST,
+                        RESET_PURGE_TX, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
                 if (result != 0) {
-                    throw new IOException("Flushing RX failed: result=" + result);
+                    throw new IOException("Purge read buffer failed: result=" + result);
                 }
             }
-            return true;
         }
+
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            int config = breakConfig;
+            if(value) config |= 0x4000;
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SET_DATA_REQUEST,
+                    config, mPortNumber+1,null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Setting BREAK failed: result=" + result);
+            }
+        }
+
+        public void setLatencyTimer(int latencyTime) throws IOException {
+            int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SET_LATENCY_TIMER_REQUEST,
+                    latencyTime, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != 0) {
+                throw new IOException("Set latency timer failed: result=" + result);
+            }
+        }
+
+        public int getLatencyTimer() throws IOException {
+            byte[] data = new byte[1];
+            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_LATENCY_TIMER_REQUEST,
+                    0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
+            if (result != data.length) {
+                throw new IOException("Get latency timer failed: result=" + result);
+            }
+            return data[0];
+        }
+
     }
 
+    @SuppressWarnings({"unused"})
     public static Map<Integer, int[]> getSupportedDevices() {
-        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<Integer, int[]>();
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_FTDI),
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_FTDI,
                 new int[] {
                     UsbId.FTDI_FT232R,
                     UsbId.FTDI_FT232H,
                     UsbId.FTDI_FT2232H,
                     UsbId.FTDI_FT4232H,
-                    UsbId.FTDI_FT231X,
+                    UsbId.FTDI_FT231X,  // same ID for FT230X, FT231X, FT234XD
                 });
         return supportedDevices;
     }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/GsmModemSerialDriver.java

@@ -0,0 +1,102 @@
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+import android.util.Log;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+public class GsmModemSerialDriver implements UsbSerialDriver{
+
+    private final String TAG = GsmModemSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final UsbSerialPort mPort;
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return Collections.singletonList(mPort);
+    }
+
+    public GsmModemSerialDriver(UsbDevice mDevice) {
+        this.mDevice = mDevice;
+        mPort = new GsmModemSerialPort(mDevice, 0);
+    }
+
+    public class GsmModemSerialPort extends CommonUsbSerialPort {
+
+        private UsbInterface mDataInterface;
+
+        public GsmModemSerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());
+            mDataInterface = mDevice.getInterface(0);
+            if (!mConnection.claimInterface(mDataInterface, true)) {
+                throw new IOException("Could not claim shared control/data interface");
+            }
+            Log.d(TAG, "endpoint count=" + mDataInterface.getEndpointCount());
+            for (int i = 0; i < mDataInterface.getEndpointCount(); ++i) {
+                UsbEndpoint ep = mDataInterface.getEndpoint(i);
+                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mReadEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mWriteEndpoint = ep;
+                }
+            }
+            initGsmModem();
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                mConnection.releaseInterface(mDataInterface);
+            } catch(Exception ignored) {}
+
+        }
+
+        private int initGsmModem() throws IOException {
+            int len = mConnection.controlTransfer(
+                    0x21, 0x22, 0x01, 0, null, 0, 5000);
+            if(len < 0) {
+                throw new IOException("init failed");
+            }
+            return len;
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return GsmModemSerialDriver.this;
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
+            throw new UnsupportedOperationException();
+        }
+
+    }
+
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_UNISOC, new int[]{
+                UsbId.FIBOCOM_L610,
+                UsbId.FIBOCOM_L612,
+        });
+        return supportedDevices;
+    }
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProbeTable.java

@@ -1,26 +1,12 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
 package com.hoho.android.usbserial.driver;
 
+import android.hardware.usb.UsbDevice;
 import android.util.Pair;
 
 import java.lang.reflect.InvocationTargetException;
@@ -29,14 +15,14 @@ import java.util.LinkedHashMap;
 import java.util.Map;
 
 /**
- * Maps (vendor id, product id) pairs to the corresponding serial driver.
- *
- * @author mike wakerly (opensource@hoho.com)
+ * Maps (vendor id, product id) pairs to the corresponding serial driver,
+ * or invoke 'probe' method to check actual USB devices for matching interfaces.
  */
 public class ProbeTable {
 
-    private final Map<Pair<Integer, Integer>, Class<? extends UsbSerialDriver>> mProbeTable =
-            new LinkedHashMap<Pair<Integer,Integer>, Class<? extends UsbSerialDriver>>();
+    private final Map<Pair<Integer, Integer>, Class<? extends UsbSerialDriver>> mVidPidProbeTable =
+            new LinkedHashMap<>();
+    private final Map<Method, Class<? extends UsbSerialDriver>> mMethodProbeTable = new LinkedHashMap<>();
 
     /**
      * Adds or updates a (vendor, product) pair in the table.
@@ -48,7 +34,7 @@ public class ProbeTable {
      */
     public ProbeTable addProduct(int vendorId, int productId,
             Class<? extends UsbSerialDriver> driverClass) {
-        mProbeTable.put(Pair.create(vendorId, productId), driverClass);
+        mVidPidProbeTable.put(Pair.create(vendorId, productId), driverClass);
         return this;
     }
 
@@ -56,53 +42,61 @@ public class ProbeTable {
      * Internal method to add all supported products from
      * {@code getSupportedProducts} static method.
      *
-     * @param driverClass
-     * @return
+     * @param driverClass to be added
      */
     @SuppressWarnings("unchecked")
-    ProbeTable addDriver(Class<? extends UsbSerialDriver> driverClass) {
-        final Method method;
+    void addDriver(Class<? extends UsbSerialDriver> driverClass) {
+        Method method;
 
         try {
             method = driverClass.getMethod("getSupportedDevices");
-        } catch (SecurityException e) {
-            throw new RuntimeException(e);
-        } catch (NoSuchMethodException e) {
+        } catch (SecurityException | NoSuchMethodException e) {
             throw new RuntimeException(e);
         }
 
         final Map<Integer, int[]> devices;
         try {
             devices = (Map<Integer, int[]>) method.invoke(null);
-        } catch (IllegalArgumentException e) {
-            throw new RuntimeException(e);
-        } catch (IllegalAccessException e) {
-            throw new RuntimeException(e);
-        } catch (InvocationTargetException e) {
+        } catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
             throw new RuntimeException(e);
         }
 
         for (Map.Entry<Integer, int[]> entry : devices.entrySet()) {
-            final int vendorId = entry.getKey().intValue();
+            final int vendorId = entry.getKey();
             for (int productId : entry.getValue()) {
                 addProduct(vendorId, productId, driverClass);
             }
         }
 
-        return this;
+        try {
+            method = driverClass.getMethod("probe", UsbDevice.class);
+            mMethodProbeTable.put(method, driverClass);
+        } catch (SecurityException | NoSuchMethodException ignored) {
+        }
     }
 
     /**
-     * Returns the driver for the given (vendor, product) pair, or {@code null}
-     * if no match.
+     * Returns the driver for the given USB device, or {@code null} if no match.
      *
-     * @param vendorId the USB vendor id
-     * @param productId the USB product id
+     * @param usbDevice the USB device to be probed
      * @return the driver class matching this pair, or {@code null}
      */
-    public Class<? extends UsbSerialDriver> findDriver(int vendorId, int productId) {
-        final Pair<Integer, Integer> pair = Pair.create(vendorId, productId);
-        return mProbeTable.get(pair);
+    public Class<? extends UsbSerialDriver> findDriver(final UsbDevice usbDevice) {
+        final Pair<Integer, Integer> pair = Pair.create(usbDevice.getVendorId(), usbDevice.getProductId());
+        Class<? extends UsbSerialDriver> driverClass = mVidPidProbeTable.get(pair);
+        if (driverClass != null)
+            return driverClass;
+        for (Map.Entry<Method, Class<? extends UsbSerialDriver>> entry : mMethodProbeTable.entrySet()) {
+            try {
+                Method method = entry.getKey();
+                Object o = method.invoke(null, usbDevice);
+                if((boolean)o)
+                    return entry.getValue();
+            } catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return null;
     }
 
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProlificSerialDriver.java

@@ -1,44 +1,26 @@
-/* This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
+/*
+ * Ported to usb-serial-for-android by Felix Hädicke <felixhaedicke@web.de>
  *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
+ * Based on the pyprolific driver written by Emmanuel Blot <emmanuel.blot@free.fr>
+ * See https://github.com/eblot/pyftdi
  *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
-/*
- * Ported to usb-serial-for-android
- * by Felix Hädicke <felixhaedicke@web.de>
- *
- * Based on the pyprolific driver written
- * by Emmanuel Blot <emmanuel.blot@free.fr>
- * See https://github.com/eblot/pyftdi
- */
-
 package com.hoho.android.usbserial.driver;
 
 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
-import android.hardware.usb.UsbRequest;
 import android.util.Log;
 
+import com.hoho.android.usbserial.BuildConfig;
+import com.hoho.android.usbserial.util.MonotonicClock;
+
 import java.io.IOException;
-import java.lang.reflect.Method;
-import java.nio.ByteBuffer;
 import java.util.Collections;
+import java.util.EnumSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -47,6 +29,13 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
     private final String TAG = ProlificSerialDriver.class.getSimpleName();
 
+    private final static int[] standardBaudRates = {
+            75, 150, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200, 9600, 14400, 19200,
+            28800, 38400, 57600, 115200, 128000, 134400, 161280, 201600, 230400, 268800,
+            403200, 460800, 614400, 806400, 921600, 1228800, 2457600, 3000000, 6000000
+    };
+    protected enum DeviceType { DEVICE_TYPE_01, DEVICE_TYPE_T, DEVICE_TYPE_HX, DEVICE_TYPE_HXN }
+
     private final UsbDevice mDevice;
     private final UsbSerialPort mPort;
 
@@ -72,31 +61,50 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
         private static final int USB_RECIP_INTERFACE = 0x01;
 
-        private static final int PROLIFIC_VENDOR_READ_REQUEST = 0x01;
-        private static final int PROLIFIC_VENDOR_WRITE_REQUEST = 0x01;
+        private static final int VENDOR_READ_REQUEST = 0x01;
+        private static final int VENDOR_WRITE_REQUEST = 0x01;
+        private static final int VENDOR_READ_HXN_REQUEST = 0x81;
+        private static final int VENDOR_WRITE_HXN_REQUEST = 0x80;
 
-        private static final int PROLIFIC_VENDOR_OUT_REQTYPE = UsbConstants.USB_DIR_OUT
-                | UsbConstants.USB_TYPE_VENDOR;
-
-        private static final int PROLIFIC_VENDOR_IN_REQTYPE = UsbConstants.USB_DIR_IN
-                | UsbConstants.USB_TYPE_VENDOR;
-
-        private static final int PROLIFIC_CTRL_OUT_REQTYPE = UsbConstants.USB_DIR_OUT
-                | UsbConstants.USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        private static final int VENDOR_OUT_REQTYPE = UsbConstants.USB_DIR_OUT | UsbConstants.USB_TYPE_VENDOR;
+        private static final int VENDOR_IN_REQTYPE = UsbConstants.USB_DIR_IN | UsbConstants.USB_TYPE_VENDOR;
+        private static final int CTRL_OUT_REQTYPE = UsbConstants.USB_DIR_OUT | UsbConstants.USB_TYPE_CLASS | USB_RECIP_INTERFACE;
 
         private static final int WRITE_ENDPOINT = 0x02;
         private static final int READ_ENDPOINT = 0x83;
         private static final int INTERRUPT_ENDPOINT = 0x81;
 
+        private static final int RESET_HXN_REQUEST = 0x07;
         private static final int FLUSH_RX_REQUEST = 0x08;
         private static final int FLUSH_TX_REQUEST = 0x09;
+        private static final int SET_LINE_REQUEST = 0x20; // same as CDC SET_LINE_CODING
+        private static final int SET_CONTROL_REQUEST = 0x22; // same as CDC SET_CONTROL_LINE_STATE
+        private static final int SEND_BREAK_REQUEST = 0x23; // same as CDC SEND_BREAK
+        private static final int GET_CONTROL_HXN_REQUEST = 0x80;
+        private static final int GET_CONTROL_REQUEST = 0x87;
+        private static final int STATUS_NOTIFICATION = 0xa1; // similar to CDC SERIAL_STATE but different length
 
-        private static final int SET_LINE_REQUEST = 0x20;
-        private static final int SET_CONTROL_REQUEST = 0x22;
+        /* RESET_HXN_REQUEST */
+        private static final int RESET_HXN_RX_PIPE = 1;
+        private static final int RESET_HXN_TX_PIPE = 2;
 
+        /* SET_CONTROL_REQUEST */
         private static final int CONTROL_DTR = 0x01;
         private static final int CONTROL_RTS = 0x02;
 
+        /* GET_CONTROL_REQUEST */
+        private static final int GET_CONTROL_FLAG_CD = 0x02;
+        private static final int GET_CONTROL_FLAG_DSR = 0x04;
+        private static final int GET_CONTROL_FLAG_RI = 0x01;
+        private static final int GET_CONTROL_FLAG_CTS = 0x08;
+
+        /* GET_CONTROL_HXN_REQUEST */
+        private static final int GET_CONTROL_HXN_FLAG_CD = 0x40;
+        private static final int GET_CONTROL_HXN_FLAG_DSR = 0x20;
+        private static final int GET_CONTROL_HXN_FLAG_RI = 0x80;
+        private static final int GET_CONTROL_HXN_FLAG_CTS = 0x08;
+
+        /* interrupt endpoint read */
         private static final int STATUS_FLAG_CD = 0x01;
         private static final int STATUS_FLAG_DSR = 0x02;
         private static final int STATUS_FLAG_RI = 0x08;
@@ -105,25 +113,16 @@ public class ProlificSerialDriver implements UsbSerialDriver {
         private static final int STATUS_BUFFER_SIZE = 10;
         private static final int STATUS_BYTE_IDX = 8;
 
-        private static final int DEVICE_TYPE_HX = 0;
-        private static final int DEVICE_TYPE_0 = 1;
-        private static final int DEVICE_TYPE_1 = 2;
-
-        private int mDeviceType = DEVICE_TYPE_HX;
-
-        private UsbEndpoint mReadEndpoint;
-        private UsbEndpoint mWriteEndpoint;
+        protected DeviceType mDeviceType = DeviceType.DEVICE_TYPE_HX;
         private UsbEndpoint mInterruptEndpoint;
-
         private int mControlLinesValue = 0;
-
         private int mBaudRate = -1, mDataBits = -1, mStopBits = -1, mParity = -1;
 
         private int mStatus = 0;
         private volatile Thread mReadStatusThread = null;
         private final Object mReadStatusThreadLock = new Object();
-        boolean mStopReadStatusThread = false;
-        private IOException mReadStatusException = null;
+        private boolean mStopReadStatusThread = false;
+        private Exception mReadStatusException = null;
 
 
         public ProlificSerialPort(UsbDevice device, int portNumber) {
@@ -135,54 +134,53 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             return ProlificSerialDriver.this;
         }
 
-        private final byte[] inControlTransfer(int requestType, int request,
-                int value, int index, int length) throws IOException {
+        private byte[] inControlTransfer(int requestType, int request, int value, int index, int length) throws IOException {
             byte[] buffer = new byte[length];
-            int result = mConnection.controlTransfer(requestType, request, value,
-                    index, buffer, length, USB_READ_TIMEOUT_MILLIS);
+            int result = mConnection.controlTransfer(requestType, request, value, index, buffer, length, USB_READ_TIMEOUT_MILLIS);
             if (result != length) {
-                throw new IOException(
-                        String.format("ControlTransfer with value 0x%x failed: %d",
-                                value, result));
+                throw new IOException(String.format("ControlTransfer %s 0x%x failed: %d",mDeviceType.name(), value, result));
             }
             return buffer;
         }
 
-        private final void outControlTransfer(int requestType, int request,
-                int value, int index, byte[] data) throws IOException {
+        private void outControlTransfer(int requestType, int request, int value, int index, byte[] data) throws IOException {
             int length = (data == null) ? 0 : data.length;
-            int result = mConnection.controlTransfer(requestType, request, value,
-                    index, data, length, USB_WRITE_TIMEOUT_MILLIS);
+            int result = mConnection.controlTransfer(requestType, request, value, index, data, length, USB_WRITE_TIMEOUT_MILLIS);
             if (result != length) {
-                throw new IOException(
-                        String.format("ControlTransfer with value 0x%x failed: %d",
-                                value, result));
+                throw new IOException( String.format("ControlTransfer %s 0x%x failed: %d", mDeviceType.name(), value, result));
             }
         }
 
-        private final byte[] vendorIn(int value, int index, int length)
-                throws IOException {
-            return inControlTransfer(PROLIFIC_VENDOR_IN_REQTYPE,
-                    PROLIFIC_VENDOR_READ_REQUEST, value, index, length);
+        private byte[] vendorIn(int value, int index, int length) throws IOException {
+            int request = (mDeviceType == DeviceType.DEVICE_TYPE_HXN) ? VENDOR_READ_HXN_REQUEST : VENDOR_READ_REQUEST;
+            return inControlTransfer(VENDOR_IN_REQTYPE, request, value, index, length);
         }
 
-        private final void vendorOut(int value, int index, byte[] data)
-                throws IOException {
-            outControlTransfer(PROLIFIC_VENDOR_OUT_REQTYPE,
-                    PROLIFIC_VENDOR_WRITE_REQUEST, value, index, data);
+        private void vendorOut(int value, int index, byte[] data) throws IOException {
+            int request = (mDeviceType == DeviceType.DEVICE_TYPE_HXN) ? VENDOR_WRITE_HXN_REQUEST : VENDOR_WRITE_REQUEST;
+            outControlTransfer(VENDOR_OUT_REQTYPE, request, value, index, data);
         }
 
         private void resetDevice() throws IOException {
             purgeHwBuffers(true, true);
         }
 
-        private final void ctrlOut(int request, int value, int index, byte[] data)
-                throws IOException {
-            outControlTransfer(PROLIFIC_CTRL_OUT_REQTYPE, request, value, index,
-                    data);
+        private void ctrlOut(int request, int value, int index, byte[] data) throws IOException {
+            outControlTransfer(CTRL_OUT_REQTYPE, request, value, index, data);
+        }
+
+        private boolean testHxStatus() {
+            try {
+                inControlTransfer(VENDOR_IN_REQTYPE, VENDOR_READ_REQUEST, 0x8080, 0, 1);
+                return true;
+            } catch(IOException ignored) {
+                return false;
+            }
         }
 
         private void doBlackMagic() throws IOException {
+            if (mDeviceType == DeviceType.DEVICE_TYPE_HXN)
+                return;
             vendorIn(0x8484, 0, 1);
             vendorOut(0x0404, 0, null);
             vendorIn(0x8484, 0, 1);
@@ -193,7 +191,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             vendorIn(0x8383, 0, 1);
             vendorOut(0, 1, null);
             vendorOut(1, 0, null);
-            vendorOut(2, (mDeviceType == DEVICE_TYPE_HX) ? 0x44 : 0x24, null);
+            vendorOut(2, (mDeviceType == DeviceType.DEVICE_TYPE_01) ? 0x24 : 0x44, null);
         }
 
         private void setControlLines(int newControlLinesValue) throws IOException {
@@ -201,238 +199,221 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             mControlLinesValue = newControlLinesValue;
         }
 
-        private final void readStatusThreadFunction() {
+        private void readStatusThreadFunction() {
             try {
+                byte[] buffer = new byte[STATUS_BUFFER_SIZE];
                 while (!mStopReadStatusThread) {
-                    byte[] buffer = new byte[STATUS_BUFFER_SIZE];
-                    int readBytesCount = mConnection.bulkTransfer(mInterruptEndpoint,
-                            buffer,
-                            STATUS_BUFFER_SIZE,
-                            500);
+                    long endTime = MonotonicClock.millis() + 500;
+                    int readBytesCount = mConnection.bulkTransfer(mInterruptEndpoint, buffer, STATUS_BUFFER_SIZE, 500);
+                    if(readBytesCount == -1)
+                        testConnection(MonotonicClock.millis() < endTime);
                     if (readBytesCount > 0) {
-                        if (readBytesCount == STATUS_BUFFER_SIZE) {
-                            mStatus = buffer[STATUS_BYTE_IDX] & 0xff;
+                        if (readBytesCount != STATUS_BUFFER_SIZE) {
+                            throw new IOException("Invalid status notification, expected " + STATUS_BUFFER_SIZE + " bytes, got " + readBytesCount);
+                        } else if(buffer[0] != (byte)STATUS_NOTIFICATION ) {
+                            throw new IOException("Invalid status notification, expected " + STATUS_NOTIFICATION + " request, got " + buffer[0]);
                         } else {
-                            throw new IOException(
-                                    String.format("Invalid CTS / DSR / CD / RI status buffer received, expected %d bytes, but received %d",
-                                            STATUS_BUFFER_SIZE,
-                                            readBytesCount));
+                            mStatus = buffer[STATUS_BYTE_IDX] & 0xff;
                         }
                     }
                 }
-            } catch (IOException e) {
-                mReadStatusException = e;
+            } catch (Exception e) {
+                if (isOpen())
+                    mReadStatusException = e;
             }
+            //Log.d(TAG, "end control line status thread " + mStopReadStatusThread + " " + (mReadStatusException == null ? "-" : mReadStatusException.getMessage()));
         }
 
-        private final int getStatus() throws IOException {
+        private int getStatus() throws IOException {
             if ((mReadStatusThread == null) && (mReadStatusException == null)) {
                 synchronized (mReadStatusThreadLock) {
                     if (mReadStatusThread == null) {
-                        byte[] buffer = new byte[STATUS_BUFFER_SIZE];
-                        int readBytes = mConnection.bulkTransfer(mInterruptEndpoint,
-                                buffer,
-                                STATUS_BUFFER_SIZE,
-                                100);
-                        if (readBytes != STATUS_BUFFER_SIZE) {
-                            Log.w(TAG, "Could not read initial CTS / DSR / CD / RI status");
+                        mStatus = 0;
+                        if(mDeviceType == DeviceType.DEVICE_TYPE_HXN) {
+                            byte[] data = vendorIn(GET_CONTROL_HXN_REQUEST, 0, 1);
+                            if ((data[0] & GET_CONTROL_HXN_FLAG_CTS) == 0) mStatus |= STATUS_FLAG_CTS;
+                            if ((data[0] & GET_CONTROL_HXN_FLAG_DSR) == 0) mStatus |= STATUS_FLAG_DSR;
+                            if ((data[0] & GET_CONTROL_HXN_FLAG_CD) == 0) mStatus |= STATUS_FLAG_CD;
+                            if ((data[0] & GET_CONTROL_HXN_FLAG_RI) == 0) mStatus |= STATUS_FLAG_RI;
                         } else {
-                            mStatus = buffer[STATUS_BYTE_IDX] & 0xff;
+                            byte[] data = vendorIn(GET_CONTROL_REQUEST, 0, 1);
+                            if ((data[0] & GET_CONTROL_FLAG_CTS) == 0) mStatus |= STATUS_FLAG_CTS;
+                            if ((data[0] & GET_CONTROL_FLAG_DSR) == 0) mStatus |= STATUS_FLAG_DSR;
+                            if ((data[0] & GET_CONTROL_FLAG_CD) == 0) mStatus |= STATUS_FLAG_CD;
+                            if ((data[0] & GET_CONTROL_FLAG_RI) == 0) mStatus |= STATUS_FLAG_RI;
                         }
-
-                        mReadStatusThread = new Thread(new Runnable() {
-                            @Override
-                            public void run() {
-                                readStatusThreadFunction();
-                            }
-                        });
+                        //Log.d(TAG, "start control line status thread " + mStatus);
+                        mReadStatusThread = new Thread(this::readStatusThreadFunction);
                         mReadStatusThread.setDaemon(true);
                         mReadStatusThread.start();
                     }
                 }
             }
 
-            /* throw and clear an exception which occured in the status read thread */
-            IOException readStatusException = mReadStatusException;
+            /* throw and clear an exception which occurred in the status read thread */
+            Exception readStatusException = mReadStatusException;
             if (mReadStatusException != null) {
                 mReadStatusException = null;
-                throw readStatusException;
+                throw new IOException(readStatusException);
             }
 
             return mStatus;
         }
 
-        private final boolean testStatusFlag(int flag) throws IOException {
+        private boolean testStatusFlag(int flag) throws IOException {
             return ((getStatus() & flag) == flag);
         }
 
         @Override
-        public void open(UsbDeviceConnection connection) throws IOException {
-            if (mConnection != null) {
-                throw new IOException("Already open");
-            }
-
+        public void openInt() throws IOException {
             UsbInterface usbInterface = mDevice.getInterface(0);
 
-            if (!connection.claimInterface(usbInterface, true)) {
+            if (!mConnection.claimInterface(usbInterface, true)) {
                 throw new IOException("Error claiming Prolific interface 0");
             }
 
-            mConnection = connection;
-            boolean opened = false;
-            try {
-                for (int i = 0; i < usbInterface.getEndpointCount(); ++i) {
-                    UsbEndpoint currentEndpoint = usbInterface.getEndpoint(i);
+            for (int i = 0; i < usbInterface.getEndpointCount(); ++i) {
+                UsbEndpoint currentEndpoint = usbInterface.getEndpoint(i);
 
-                    switch (currentEndpoint.getAddress()) {
-                    case READ_ENDPOINT:
-                        mReadEndpoint = currentEndpoint;
-                        break;
+                switch (currentEndpoint.getAddress()) {
+                case READ_ENDPOINT:
+                    mReadEndpoint = currentEndpoint;
+                    break;
 
-                    case WRITE_ENDPOINT:
-                        mWriteEndpoint = currentEndpoint;
-                        break;
+                case WRITE_ENDPOINT:
+                    mWriteEndpoint = currentEndpoint;
+                    break;
 
-                    case INTERRUPT_ENDPOINT:
-                        mInterruptEndpoint = currentEndpoint;
-                        break;
-                    }
-                }
-
-                if (mDevice.getDeviceClass() == 0x02) {
-                    mDeviceType = DEVICE_TYPE_0;
-                } else {
-                    try {
-                        Method getRawDescriptorsMethod
-                            = mConnection.getClass().getMethod("getRawDescriptors");
-                        byte[] rawDescriptors
-                            = (byte[]) getRawDescriptorsMethod.invoke(mConnection);
-                        byte maxPacketSize0 = rawDescriptors[7];
-                        if (maxPacketSize0 == 64) {
-                            mDeviceType = DEVICE_TYPE_HX;
-                        } else if ((mDevice.getDeviceClass() == 0x00)
-                                || (mDevice.getDeviceClass() == 0xff)) {
-                            mDeviceType = DEVICE_TYPE_1;
-                        } else {
-                          Log.w(TAG, "Could not detect PL2303 subtype, "
-                              + "Assuming that it is a HX device");
-                          mDeviceType = DEVICE_TYPE_HX;
-                        }
-                    } catch (NoSuchMethodException e) {
-                        Log.w(TAG, "Method UsbDeviceConnection.getRawDescriptors, "
-                                + "required for PL2303 subtype detection, not "
-                                + "available! Assuming that it is a HX device");
-                        mDeviceType = DEVICE_TYPE_HX;
-                    } catch (Exception e) {
-                        Log.e(TAG, "An unexpected exception occured while trying "
-                                + "to detect PL2303 subtype", e);
-                    }
-                }
-
-                setControlLines(mControlLinesValue);
-                resetDevice();
-
-                doBlackMagic();
-                opened = true;
-            } finally {
-                if (!opened) {
-                    mConnection = null;
-                    connection.releaseInterface(usbInterface);
+                case INTERRUPT_ENDPOINT:
+                    mInterruptEndpoint = currentEndpoint;
+                    break;
                 }
             }
+
+            byte[] rawDescriptors = mConnection.getRawDescriptors();
+            if(rawDescriptors == null || rawDescriptors.length < 14) {
+                throw new IOException("Could not get device descriptors");
+            }
+            int usbVersion = (rawDescriptors[3] << 8) + rawDescriptors[2];
+            int deviceVersion = (rawDescriptors[13] << 8) + rawDescriptors[12];
+            byte maxPacketSize0 = rawDescriptors[7];
+            if (mDevice.getDeviceClass() == 0x02 || maxPacketSize0 != 64) {
+                mDeviceType = DeviceType.DEVICE_TYPE_01;
+            } else if(usbVersion == 0x200) {
+                if(deviceVersion == 0x300 && testHxStatus()) {
+                    mDeviceType = DeviceType.DEVICE_TYPE_T; // TA
+                } else if(deviceVersion == 0x500 && testHxStatus()) {
+                    mDeviceType = DeviceType.DEVICE_TYPE_T; // TB
+                } else {
+                    mDeviceType = DeviceType.DEVICE_TYPE_HXN;
+                }
+            } else {
+                mDeviceType = DeviceType.DEVICE_TYPE_HX;
+            }
+            Log.d(TAG, String.format("usbVersion=%x, deviceVersion=%x, deviceClass=%d, packetSize=%d => deviceType=%s",
+                    usbVersion, deviceVersion, mDevice.getDeviceClass(), maxPacketSize0, mDeviceType.name()));
+            resetDevice();
+            doBlackMagic();
+            setControlLines(mControlLinesValue);
+            setFlowControl(mFlowControl);
         }
 
         @Override
-        public void close() throws IOException {
-            if (mConnection == null) {
-                throw new IOException("Already closed");
-            }
+        public void closeInt() {
             try {
-                mStopReadStatusThread = true;
                 synchronized (mReadStatusThreadLock) {
                     if (mReadStatusThread != null) {
                         try {
+                            mStopReadStatusThread = true;
                             mReadStatusThread.join();
                         } catch (Exception e) {
                             Log.w(TAG, "An error occured while waiting for status read thread", e);
                         }
+                        mStopReadStatusThread = false;
+                        mReadStatusThread = null;
+                        mReadStatusException = null;
                     }
                 }
                 resetDevice();
-            } finally {
-                try {
-                    mConnection.releaseInterface(mDevice.getInterface(0));
-                } finally {
-                    mConnection = null;
-                }
-            }
-        }
-
-        @Override
-        public int read(byte[] dest, int timeoutMillis) throws IOException {
-            final UsbRequest request = new UsbRequest();
+            } catch(Exception ignored) {}
             try {
-                request.initialize(mConnection, mReadEndpoint);
-                final ByteBuffer buf = ByteBuffer.wrap(dest);
-                if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
-                }
-
-                final UsbRequest response = mConnection.requestWait();
-                if (response == null) {
-                    throw new IOException("Null response");
-                }
-
-                final int nread = buf.position();
-                if (nread > 0) {
-                    //Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, dest.length)));
-                    return nread;
-                } else {
-                    return 0;
-                }
-            } finally {
-                request.close();
-            }
+                mConnection.releaseInterface(mDevice.getInterface(0));
+            } catch(Exception ignored) {}
         }
 
-        @Override
-        public int write(byte[] src, int timeoutMillis) throws IOException {
-            int offset = 0;
-
-            while (offset < src.length) {
-                final int writeLength;
-                final int amtWritten;
-
-                synchronized (mWriteBufferLock) {
-                    final byte[] writeBuffer;
-
-                    writeLength = Math.min(src.length - offset, mWriteBuffer.length);
-                    if (offset == 0) {
-                        writeBuffer = src;
-                    } else {
-                        // bulkTransfer does not support offsets, make a copy.
-                        System.arraycopy(src, offset, mWriteBuffer, 0, writeLength);
-                        writeBuffer = mWriteBuffer;
+        private int filterBaudRate(int baudRate) {
+            if(BuildConfig.DEBUG && (baudRate & (3<<29)) == (1<<29)) {
+                return baudRate & ~(1<<29); // for testing purposes accept without further checks
+            }
+            if (baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            if (mDeviceType == DeviceType.DEVICE_TYPE_HXN) {
+                return baudRate;
+            }
+            for(int br : standardBaudRates) {
+                if (br == baudRate) {
+                    return baudRate;
+                }
+            }
+            /*
+             * Formula taken from Linux + FreeBSD.
+             *
+             * For TA+TB devices
+             *   baudrate = baseline / (mantissa * 2^exponent)
+             * where
+             *   mantissa = buf[10:0]
+             *   exponent = buf[15:13 16]
+             *
+             * For other devices
+             *   baudrate = baseline / (mantissa * 4^exponent)
+             * where
+             *   mantissa = buf[8:0]
+             *   exponent = buf[11:9]
+             *
+             */
+            int baseline, mantissa, exponent, buf, effectiveBaudRate;
+            baseline = 12000000 * 32;
+            mantissa = baseline / baudRate;
+            if (mantissa == 0) { // > unrealistic 384 MBaud
+                throw new UnsupportedOperationException("Baud rate to high");
+            }
+            exponent = 0;
+            if (mDeviceType == DeviceType.DEVICE_TYPE_T) {
+                while (mantissa >= 2048) {
+                    if (exponent < 15) {
+                        mantissa >>= 1;    /* divide by 2 */
+                        exponent++;
+                    } else { // < 7 baud
+                        throw new UnsupportedOperationException("Baud rate to low");
                     }
-
-                    amtWritten = mConnection.bulkTransfer(mWriteEndpoint,
-                            writeBuffer, writeLength, timeoutMillis);
                 }
-
-                if (amtWritten <= 0) {
-                    throw new IOException("Error writing " + writeLength
-                            + " bytes at offset " + offset + " length="
-                            + src.length);
+                buf = mantissa + ((exponent & ~1) << 12) + ((exponent & 1) << 16) + (1 << 31);
+                effectiveBaudRate = (baseline / mantissa) >> exponent;
+            } else {
+                while (mantissa >= 512) {
+                    if (exponent < 7) {
+                        mantissa >>= 2;    /* divide by 4 */
+                        exponent++;
+                    } else { // < 45.8 baud
+                        throw new UnsupportedOperationException("Baud rate to low");
+                    }
                 }
-
-                offset += amtWritten;
+                buf = mantissa + (exponent << 9) + (1 << 31);
+                effectiveBaudRate = (baseline / mantissa) >> (exponent << 1);
             }
-            return offset;
+            double baudRateError = Math.abs(1.0 - (effectiveBaudRate / (double)baudRate));
+            if(baudRateError >= 0.031) // > unrealistic 11.6 Mbaud
+                throw new UnsupportedOperationException(String.format("Baud rate deviation %.1f%% is higher than allowed 3%%", baudRateError*100));
+
+            Log.d(TAG, String.format("baud rate=%d, effective=%d, error=%.1f%%, value=0x%08x, mantissa=%d, exponent=%d",
+                    baudRate, effectiveBaudRate, baudRateError*100, buf, mantissa, exponent));
+            return buf;
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits,
-                int parity) throws IOException {
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            baudRate = filterBaudRate(baudRate);
             if ((mBaudRate == baudRate) && (mDataBits == dataBits)
                     && (mStopBits == stopBits) && (mParity == parity)) {
                 // Make sure no action is performed if there is nothing to change
@@ -440,7 +421,6 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             }
 
             byte[] lineRequestData = new byte[7];
-
             lineRequestData[0] = (byte) (baudRate & 0xff);
             lineRequestData[1] = (byte) ((baudRate >> 8) & 0xff);
             lineRequestData[2] = (byte) ((baudRate >> 16) & 0xff);
@@ -450,44 +430,39 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             case STOPBITS_1:
                 lineRequestData[4] = 0;
                 break;
-
             case STOPBITS_1_5:
                 lineRequestData[4] = 1;
                 break;
-
             case STOPBITS_2:
                 lineRequestData[4] = 2;
                 break;
-
             default:
-                throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
 
             switch (parity) {
             case PARITY_NONE:
                 lineRequestData[5] = 0;
                 break;
-
             case PARITY_ODD:
                 lineRequestData[5] = 1;
                 break;
-            
             case PARITY_EVEN:
                 lineRequestData[5] = 2;
                 break;
-
             case PARITY_MARK:
                 lineRequestData[5] = 3;
                 break;
-
             case PARITY_SPACE:
                 lineRequestData[5] = 4;
                 break;
-
             default:
-                throw new IllegalArgumentException("Unknown parity value: " + parity);
+                throw new IllegalArgumentException("Invalid parity: " + parity);
             }
 
+            if(dataBits < DATABITS_5 || dataBits > DATABITS_8) {
+                throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }
             lineRequestData[6] = (byte) dataBits;
 
             ctrlOut(SET_LINE_REQUEST, 0, 0, lineRequestData);
@@ -517,7 +492,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
         @Override
         public boolean getDTR() throws IOException {
-            return ((mControlLinesValue & CONTROL_DTR) == CONTROL_DTR);
+            return (mControlLinesValue & CONTROL_DTR) != 0;
         }
 
         @Override
@@ -538,7 +513,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
         @Override
         public boolean getRTS() throws IOException {
-            return ((mControlLinesValue & CONTROL_RTS) == CONTROL_RTS);
+            return (mControlLinesValue & CONTROL_RTS) != 0;
         }
 
         @Override
@@ -553,23 +528,91 @@ public class ProlificSerialDriver implements UsbSerialDriver {
         }
 
         @Override
-        public boolean purgeHwBuffers(boolean purgeReadBuffers, boolean purgeWriteBuffers) throws IOException {
-            if (purgeReadBuffers) {
-                vendorOut(FLUSH_RX_REQUEST, 0, null);
-            }
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            int status = getStatus();
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            if((mControlLinesValue & CONTROL_RTS) != 0) set.add(ControlLine.RTS);
+            if((status & STATUS_FLAG_CTS) != 0) set.add(ControlLine.CTS);
+            if((mControlLinesValue & CONTROL_DTR) != 0) set.add(ControlLine.DTR);
+            if((status & STATUS_FLAG_DSR) != 0) set.add(ControlLine.DSR);
+            if((status & STATUS_FLAG_CD) != 0) set.add(ControlLine.CD);
+            if((status & STATUS_FLAG_RI) != 0) set.add(ControlLine.RI);
+            return set;
+        }
 
-            if (purgeWriteBuffers) {
-                vendorOut(FLUSH_TX_REQUEST, 0, null);
-            }
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.allOf(ControlLine.class);
+        }
 
-            return purgeReadBuffers || purgeWriteBuffers;
+        @Override
+        public void setFlowControl(FlowControl flowControl) throws IOException {
+            // vendorOut values from https://www.mail-archive.com/linux-usb@vger.kernel.org/msg110968.html
+            switch (flowControl) {
+                case NONE:
+                    if (mDeviceType == DeviceType.DEVICE_TYPE_HXN)
+                        vendorOut(0x0a, 0xff, null);
+                    else
+                        vendorOut(0, 0, null);
+                    break;
+                case RTS_CTS:
+                    if (mDeviceType == DeviceType.DEVICE_TYPE_HXN)
+                        vendorOut(0x0a, 0xfa, null);
+                    else
+                        vendorOut(0, 0x61, null);
+                    break;
+                case XON_XOFF_INLINE:
+                    if (mDeviceType == DeviceType.DEVICE_TYPE_HXN)
+                        vendorOut(0x0a, 0xee, null);
+                    else
+                        vendorOut(0, 0xc1, null);
+                    break;
+                default:
+                    throw new UnsupportedOperationException();
+            }
+            mFlowControl = flowControl;
+        }
+
+        @Override
+        public EnumSet<FlowControl> getSupportedFlowControl() {
+            return EnumSet.of(FlowControl.NONE, FlowControl.RTS_CTS, FlowControl.XON_XOFF_INLINE);
+        }
+
+        @Override
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+            if (mDeviceType == DeviceType.DEVICE_TYPE_HXN) {
+                int index = 0;
+                if(purgeWriteBuffers) index |= RESET_HXN_RX_PIPE;
+                if(purgeReadBuffers) index |= RESET_HXN_TX_PIPE;
+                if(index != 0)
+                    vendorOut(RESET_HXN_REQUEST, index, null);
+            } else {
+                if (purgeWriteBuffers)
+                    vendorOut(FLUSH_RX_REQUEST, 0, null);
+                if (purgeReadBuffers)
+                    vendorOut(FLUSH_TX_REQUEST, 0, null);
+            }
+        }
+
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            ctrlOut(SEND_BREAK_REQUEST, value ? 0xffff : 0, 0, null);
         }
     }
 
+    @SuppressWarnings({"unused"})
     public static Map<Integer, int[]> getSupportedDevices() {
-        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<Integer, int[]>();
-        supportedDevices.put(Integer.valueOf(UsbId.VENDOR_PROLIFIC),
-                new int[] { UsbId.PROLIFIC_PL2303, });
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_PROLIFIC,
+                new int[] {
+                        UsbId.PROLIFIC_PL2303,
+                        UsbId.PROLIFIC_PL2303GC,
+                        UsbId.PROLIFIC_PL2303GB,
+                        UsbId.PROLIFIC_PL2303GT,
+                        UsbId.PROLIFIC_PL2303GL,
+                        UsbId.PROLIFIC_PL2303GE,
+                        UsbId.PROLIFIC_PL2303GS,
+                });
         return supportedDevices;
     }
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/SerialTimeoutException.java

@@ -0,0 +1,16 @@
+package com.hoho.android.usbserial.driver;
+
+import java.io.InterruptedIOException;
+
+/**
+ * Signals that a timeout has occurred on serial write.
+ * Similar to SocketTimeoutException.
+ *
+ * {@see InterruptedIOException#bytesTransferred} may contain bytes transferred
+ */
+public class SerialTimeoutException extends InterruptedIOException {
+    public SerialTimeoutException(String s, int bytesTransferred) {
+        super(s);
+        this.bytesTransferred = bytesTransferred;
+    }
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbId.java

@@ -1,21 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
@@ -36,47 +21,36 @@ public final class UsbId {
     public static final int FTDI_FT2232H = 0x6010;
     public static final int FTDI_FT4232H = 0x6011;
     public static final int FTDI_FT232H = 0x6014;
-    public static final int FTDI_FT231X = 0x6015;
-
-    public static final int VENDOR_ATMEL = 0x03EB;
-    public static final int ATMEL_LUFA_CDC_DEMO_APP = 0x2044;
-
-    public static final int VENDOR_ARDUINO = 0x2341;
-    public static final int ARDUINO_UNO = 0x0001;
-    public static final int ARDUINO_MEGA_2560 = 0x0010;
-    public static final int ARDUINO_SERIAL_ADAPTER = 0x003b;
-    public static final int ARDUINO_MEGA_ADK = 0x003f;
-    public static final int ARDUINO_MEGA_2560_R3 = 0x0042;
-    public static final int ARDUINO_UNO_R3 = 0x0043;
-    public static final int ARDUINO_MEGA_ADK_R3 = 0x0044;
-    public static final int ARDUINO_SERIAL_ADAPTER_R3 = 0x0044;
-    public static final int ARDUINO_LEONARDO = 0x8036;
-    public static final int ARDUINO_MICRO = 0x8037;
-
-    public static final int VENDOR_VAN_OOIJEN_TECH = 0x16c0;
-    public static final int VAN_OOIJEN_TECH_TEENSYDUINO_SERIAL = 0x0483;
-
-    public static final int VENDOR_LEAFLABS = 0x1eaf;
-    public static final int LEAFLABS_MAPLE = 0x0004;
+    public static final int FTDI_FT231X = 0x6015; // same ID for FT230X, FT231X, FT234XD
 
     public static final int VENDOR_SILABS = 0x10c4;
-    public static final int SILABS_CP2102 = 0xea60;
+    public static final int SILABS_CP2102 = 0xea60; // same ID for CP2101, CP2103, CP2104, CP2109
     public static final int SILABS_CP2105 = 0xea70;
     public static final int SILABS_CP2108 = 0xea71;
-    public static final int SILABS_CP2110 = 0xea80;
 
     public static final int VENDOR_PROLIFIC = 0x067b;
-    public static final int PROLIFIC_PL2303 = 0x2303;
+    public static final int PROLIFIC_PL2303 = 0x2303;   // device type 01, T, HX
+    public static final int PROLIFIC_PL2303GC = 0x23a3; // device type HXN
+    public static final int PROLIFIC_PL2303GB = 0x23b3; // "
+    public static final int PROLIFIC_PL2303GT = 0x23c3; // "
+    public static final int PROLIFIC_PL2303GL = 0x23d3; // "
+    public static final int PROLIFIC_PL2303GE = 0x23e3; // "
+    public static final int PROLIFIC_PL2303GS = 0x23f3; // "
+
+    public static final int VENDOR_GOOGLE = 0x18d1;
+    public static final int GOOGLE_CR50 = 0x5014;
 
     public static final int VENDOR_QINHENG = 0x1a86;
-    public static final int QINHENG_HL340 = 0x7523;
+    public static final int QINHENG_CH340 = 0x7523;
+    public static final int QINHENG_CH341A = 0x5523;
+
+    public static final int VENDOR_UNISOC = 0x1782;
+    public static final int FIBOCOM_L610 = 0x4D10;
+    public static final int FIBOCOM_L612 = 0x4D12;
 
-    // at www.linux-usb.org/usb.ids listed for NXP/LPC1768, but all processors supported by ARM mbed DAPLink firmware report these ids
-    public static final int VENDOR_ARM = 0x0d28;
-    public static final int ARM_MBED = 0x0204;
 
     private UsbId() {
-        throw new IllegalAccessError("Non-instantiable class.");
+        throw new IllegalAccessError("Non-instantiable class");
     }
 
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialDriver.java

@@ -1,21 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
@@ -25,18 +10,23 @@ import android.hardware.usb.UsbDevice;
 
 import java.util.List;
 
-/**
- *
- * @author mike wakerly (opensource@hoho.com)
- */
 public interface UsbSerialDriver {
 
+    /*
+     * Additional interface properties. Invoked thru reflection.
+     *
+        UsbSerialDriver(UsbDevice device);                  // constructor with device
+        static Map<Integer, int[]> getSupportedDevices();
+        static boolean probe(UsbDevice device);             // optional
+     */
+
+
     /**
      * Returns the raw {@link UsbDevice} backing this port.
      *
      * @return the device
      */
-    public UsbDevice getDevice();
+    UsbDevice getDevice();
 
     /**
      * Returns all available ports for this device. This list must have at least
@@ -44,5 +34,5 @@ public interface UsbSerialDriver {
      *
      * @return the ports
      */
-    public List<UsbSerialPort> getPorts();
+    List<UsbSerialPort> getPorts();
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialPort.java

@@ -1,228 +1,324 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
 package com.hoho.android.usbserial.driver;
 
+import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbManager;
 
+import androidx.annotation.IntDef;
+
+import java.io.Closeable;
 import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.EnumSet;
 
 /**
  * Interface for a single serial port.
  *
  * @author mike wakerly (opensource@hoho.com)
  */
-public interface UsbSerialPort {
+public interface UsbSerialPort extends Closeable {
 
     /** 5 data bits. */
-    public static final int DATABITS_5 = 5;
-
+    int DATABITS_5 = 5;
     /** 6 data bits. */
-    public static final int DATABITS_6 = 6;
-
+    int DATABITS_6 = 6;
     /** 7 data bits. */
-    public static final int DATABITS_7 = 7;
-
+    int DATABITS_7 = 7;
     /** 8 data bits. */
-    public static final int DATABITS_8 = 8;
-
-    /** No flow control. */
-    public static final int FLOWCONTROL_NONE = 0;
-
-    /** RTS/CTS input flow control. */
-    public static final int FLOWCONTROL_RTSCTS_IN = 1;
-
-    /** RTS/CTS output flow control. */
-    public static final int FLOWCONTROL_RTSCTS_OUT = 2;
-
-    /** XON/XOFF input flow control. */
-    public static final int FLOWCONTROL_XONXOFF_IN = 4;
-
-    /** XON/XOFF output flow control. */
-    public static final int FLOWCONTROL_XONXOFF_OUT = 8;
+    int DATABITS_8 = 8;
 
+    /** Values for setParameters(..., parity) */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({PARITY_NONE, PARITY_ODD, PARITY_EVEN, PARITY_MARK, PARITY_SPACE})
+    @interface Parity {}
     /** No parity. */
-    public static final int PARITY_NONE = 0;
-
+    int PARITY_NONE = 0;
     /** Odd parity. */
-    public static final int PARITY_ODD = 1;
-
+    int PARITY_ODD = 1;
     /** Even parity. */
-    public static final int PARITY_EVEN = 2;
-
+    int PARITY_EVEN = 2;
     /** Mark parity. */
-    public static final int PARITY_MARK = 3;
-
+    int PARITY_MARK = 3;
     /** Space parity. */
-    public static final int PARITY_SPACE = 4;
+    int PARITY_SPACE = 4;
 
     /** 1 stop bit. */
-    public static final int STOPBITS_1 = 1;
-
+    int STOPBITS_1 = 1;
     /** 1.5 stop bits. */
-    public static final int STOPBITS_1_5 = 3;
-
+    int STOPBITS_1_5 = 3;
     /** 2 stop bits. */
-    public static final int STOPBITS_2 = 2;
+    int STOPBITS_2 = 2;
+
+    /** Values for get[Supported]ControlLines() */
+    enum ControlLine { RTS, CTS, DTR, DSR, CD, RI }
+
+    /** Values for (set|get|getSupported)FlowControl() */
+    enum FlowControl { NONE, RTS_CTS, DTR_DSR, XON_XOFF, XON_XOFF_INLINE }
+
+    /** XON character used with flow control XON/XOFF */
+    char CHAR_XON = 17;
+    /** XOFF character used with flow control XON/XOFF */
+    char CHAR_XOFF = 19;
+
+
+    /**
+     * Returns the driver used by this port.
+     */
+    UsbSerialDriver getDriver();
+
+    /**
+     * Returns the currently-bound USB device.
+     */
+    UsbDevice getDevice();
 
-    public UsbSerialDriver getDriver();
-    
     /**
      * Port number within driver.
      */
-    public int getPortNumber();
-    
+    int getPortNumber();
+
+    /**
+     * Returns the write endpoint.
+     * @return write endpoint
+     */
+    UsbEndpoint getWriteEndpoint();
+
+    /**
+     * Returns the read endpoint.
+     * @return read endpoint
+     */
+    UsbEndpoint getReadEndpoint();
+
     /**
      * The serial number of the underlying UsbDeviceConnection, or {@code null}.
+     *
+     * @return value from {@link UsbDeviceConnection#getSerial()}
+     * @throws SecurityException starting with target SDK 29 (Android 10) if permission for USB device is not granted
      */
-    public String getSerial();
+    String getSerial();
 
     /**
      * Opens and initializes the port. Upon success, caller must ensure that
      * {@link #close()} is eventually called.
      *
      * @param connection an open device connection, acquired with
-     *            {@link UsbManager#openDevice(android.hardware.usb.UsbDevice)}
+     *                   {@link UsbManager#openDevice(android.hardware.usb.UsbDevice)}
      * @throws IOException on error opening or initializing the port.
      */
-    public void open(UsbDeviceConnection connection) throws IOException;
+    void open(UsbDeviceConnection connection) throws IOException;
 
     /**
-     * Closes the port.
+     * Closes the port and {@link UsbDeviceConnection}
      *
      * @throws IOException on error closing the port.
      */
-    public void close() throws IOException;
+    void close() throws IOException;
 
     /**
      * Reads as many bytes as possible into the destination buffer.
      *
      * @param dest the destination byte buffer
-     * @param timeoutMillis the timeout for reading
+     * @param timeout the timeout for reading in milliseconds, 0 is infinite
      * @return the actual number of bytes read
      * @throws IOException if an error occurred during reading
      */
-    public int read(final byte[] dest, final int timeoutMillis) throws IOException;
+    int read(final byte[] dest, final int timeout) throws IOException;
+
+    /**
+     * Reads bytes with specified length into the destination buffer.
+     *
+     * @param dest the destination byte buffer
+     * @param length the maximum length of the data to read
+     * @param timeout the timeout for reading in milliseconds, 0 is infinite
+     * @return the actual number of bytes read
+     * @throws IOException if an error occurred during reading
+     */
+    int read(final byte[] dest, int length, final int timeout) throws IOException;
 
     /**
      * Writes as many bytes as possible from the source buffer.
      *
      * @param src the source byte buffer
-     * @param timeoutMillis the timeout for writing
-     * @return the actual number of bytes written
+     * @param timeout the timeout for writing in milliseconds, 0 is infinite
+     * @throws SerialTimeoutException if timeout reached before sending all data.
+     *                                ex.bytesTransferred may contain bytes transferred
      * @throws IOException if an error occurred during writing
      */
-    public int write(final byte[] src, final int timeoutMillis) throws IOException;
+    void write(final byte[] src, final int timeout) throws IOException;
+
+    /**
+     * Writes bytes with specified length from the source buffer.
+     *
+     * @param src the source byte buffer
+     * @param length the length of the data to write
+     * @param timeout the timeout for writing in milliseconds, 0 is infinite
+     * @throws SerialTimeoutException if timeout reached before sending all data.
+     *                                ex.bytesTransferred may contain bytes transferred
+     * @throws IOException if an error occurred during writing
+     */
+    void write(final byte[] src, int length, final int timeout) throws IOException;
 
     /**
      * Sets various serial port parameters.
      *
      * @param baudRate baud rate as an integer, for example {@code 115200}.
      * @param dataBits one of {@link #DATABITS_5}, {@link #DATABITS_6},
-     *            {@link #DATABITS_7}, or {@link #DATABITS_8}.
-     * @param stopBits one of {@link #STOPBITS_1}, {@link #STOPBITS_1_5}, or
-     *            {@link #STOPBITS_2}.
+     *                 {@link #DATABITS_7}, or {@link #DATABITS_8}.
+     * @param stopBits one of {@link #STOPBITS_1}, {@link #STOPBITS_1_5}, or {@link #STOPBITS_2}.
      * @param parity one of {@link #PARITY_NONE}, {@link #PARITY_ODD},
-     *            {@link #PARITY_EVEN}, {@link #PARITY_MARK}, or
-     *            {@link #PARITY_SPACE}.
+     *               {@link #PARITY_EVEN}, {@link #PARITY_MARK}, or {@link #PARITY_SPACE}.
      * @throws IOException on error setting the port parameters
+     * @throws UnsupportedOperationException if not supported or values are not supported by a specific device
      */
-    public void setParameters(
-            int baudRate, int dataBits, int stopBits, int parity) throws IOException;
+    void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException;
 
     /**
      * Gets the CD (Carrier Detect) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getCD() throws IOException;
+    boolean getCD() throws IOException;
 
     /**
      * Gets the CTS (Clear To Send) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getCTS() throws IOException;
+    boolean getCTS() throws IOException;
 
     /**
      * Gets the DSR (Data Set Ready) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getDSR() throws IOException;
+    boolean getDSR() throws IOException;
 
     /**
      * Gets the DTR (Data Terminal Ready) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getDTR() throws IOException;
+    boolean getDTR() throws IOException;
 
     /**
-     * Sets the DTR (Data Terminal Ready) bit on the underlying UART, if
-     * supported.
+     * Sets the DTR (Data Terminal Ready) bit on the underlying UART, if supported.
      *
      * @param value the value to set
      * @throws IOException if an error occurred during writing
+     * @throws UnsupportedOperationException if not supported
      */
-    public void setDTR(boolean value) throws IOException;
+    void setDTR(boolean value) throws IOException;
 
     /**
      * Gets the RI (Ring Indicator) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getRI() throws IOException;
+    boolean getRI() throws IOException;
 
     /**
      * Gets the RTS (Request To Send) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean getRTS() throws IOException;
+    boolean getRTS() throws IOException;
 
     /**
-     * Sets the RTS (Request To Send) bit on the underlying UART, if
-     * supported.
+     * Sets the RTS (Request To Send) bit on the underlying UART, if supported.
      *
      * @param value the value to set
      * @throws IOException if an error occurred during writing
+     * @throws UnsupportedOperationException if not supported
      */
-    public void setRTS(boolean value) throws IOException;
+    void setRTS(boolean value) throws IOException;
 
     /**
-     * Flush non-transmitted output data and / or non-read input data
-     * @param flushRX {@code true} to flush non-transmitted output data
-     * @param flushTX {@code true} to flush non-read input data
-     * @return {@code true} if the operation was successful, or
-     * {@code false} if the operation is not supported by the driver or device
-     * @throws IOException if an error occurred during flush
+     * Gets all control line values from the underlying UART, if supported.
+     * Requires less USB calls than calling getRTS() + ... + getRI() individually.
+     *
+     * @return EnumSet.contains(...) is {@code true} if set, else {@code false}
+     * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean purgeHwBuffers(boolean flushRX, boolean flushTX) throws IOException;
+    EnumSet<ControlLine> getControlLines() throws IOException;
+
+    /**
+     * Gets all control line supported flags.
+     *
+     * @return EnumSet.contains(...) is {@code true} if supported, else {@code false}
+     * @throws IOException if an error occurred during reading
+     */
+    EnumSet<ControlLine> getSupportedControlLines() throws IOException;
+
+    /**
+     * Set flow control mode, if supported
+     * @param flowControl @FlowControl
+     * @throws IOException if an error occurred during writing
+     * @throws UnsupportedOperationException if not supported
+     */
+    void setFlowControl(FlowControl flowControl) throws IOException;
+
+    /**
+     * Get flow control mode.
+     * @return FlowControl
+     */
+    FlowControl getFlowControl();
+
+    /**
+     * Get supported flow control modes
+     * @return EnumSet.contains(...) is {@code true} if supported, else {@code false}
+     */
+    EnumSet<FlowControl> getSupportedFlowControl();
+
+    /**
+     * If flow control = XON_XOFF, indicates that send is enabled by XON.
+     * Devices supporting flow control = XON_XOFF_INLINE return CHAR_XON/CHAR_XOFF in read() data.
+     *
+     * @return the current state
+     * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
+     */
+    boolean getXON() throws IOException;
+
+    /**
+     * Purge non-transmitted output data and / or non-read input data.
+     *
+     * @param purgeWriteBuffers {@code true} to discard non-transmitted output data
+     * @param purgeReadBuffers {@code true} to discard non-read input data
+     * @throws IOException if an error occurred during flush
+     * @throws UnsupportedOperationException if not supported
+     */
+    void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException;
+
+    /**
+     * send BREAK condition.
+     *
+     * @param value set/reset
+     */
+    void setBreak(boolean value) throws IOException;
+
+    /**
+     * Returns the current state of the connection.
+     */
+    boolean isOpen();
 
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialProber.java

@@ -1,21 +1,6 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
@@ -52,6 +37,8 @@ public class UsbSerialProber {
         probeTable.addDriver(FtdiSerialDriver.class);
         probeTable.addDriver(ProlificSerialDriver.class);
         probeTable.addDriver(Ch34xSerialDriver.class);
+        probeTable.addDriver(GsmModemSerialDriver.class);
+        probeTable.addDriver(ChromeCcdSerialDriver.class);
         return probeTable;
     }
 
@@ -61,11 +48,11 @@ public class UsbSerialProber {
      * not require permission from the Android USB system, since it does not
      * open any of the devices.
      *
-     * @param usbManager
+     * @param usbManager usb manager
      * @return a list, possibly empty, of all compatible drivers
      */
     public List<UsbSerialDriver> findAllDrivers(final UsbManager usbManager) {
-        final List<UsbSerialDriver> result = new ArrayList<UsbSerialDriver>();
+        final List<UsbSerialDriver> result = new ArrayList<>();
 
         for (final UsbDevice usbDevice : usbManager.getDeviceList().values()) {
             final UsbSerialDriver driver = probeDevice(usbDevice);
@@ -84,26 +71,15 @@ public class UsbSerialProber {
      *         {@code null} if none available.
      */
     public UsbSerialDriver probeDevice(final UsbDevice usbDevice) {
-        final int vendorId = usbDevice.getVendorId();
-        final int productId = usbDevice.getProductId();
-
-        final Class<? extends UsbSerialDriver> driverClass =
-                mProbeTable.findDriver(vendorId, productId);
+        final Class<? extends UsbSerialDriver> driverClass = mProbeTable.findDriver(usbDevice);
         if (driverClass != null) {
             final UsbSerialDriver driver;
             try {
                 final Constructor<? extends UsbSerialDriver> ctor =
                         driverClass.getConstructor(UsbDevice.class);
                 driver = ctor.newInstance(usbDevice);
-            } catch (NoSuchMethodException e) {
-                throw new RuntimeException(e);
-            } catch (IllegalArgumentException e) {
-                throw new RuntimeException(e);
-            } catch (InstantiationException e) {
-                throw new RuntimeException(e);
-            } catch (IllegalAccessException e) {
-                throw new RuntimeException(e);
-            } catch (InvocationTargetException e) {
+            } catch (NoSuchMethodException | IllegalArgumentException | InstantiationException |
+                     IllegalAccessException | InvocationTargetException e) {
                 throw new RuntimeException(e);
             }
             return driver;

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialRuntimeException.java

@@ -1,46 +0,0 @@
-/*
- * Copyright 2011 Google Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- */
-
-package com.hoho.android.usbserial.driver;
-
-/**
- * Generic unchecked exception for the usbserial package.
- *
- * @author mike wakerly (opensource@hoho.com)
- */
-@SuppressWarnings("serial")
-public class UsbSerialRuntimeException extends RuntimeException {
-
-    public UsbSerialRuntimeException() {
-        super();
-    }
-
-    public UsbSerialRuntimeException(String detailMessage, Throwable throwable) {
-        super(detailMessage, throwable);
-    }
-
-    public UsbSerialRuntimeException(String detailMessage) {
-        super(detailMessage);
-    }
-
-    public UsbSerialRuntimeException(Throwable throwable) {
-        super(throwable);
-    }
-
-}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/HexDump.java

@@ -16,15 +16,20 @@
 
 package com.hoho.android.usbserial.util;
 
+import java.security.InvalidParameterException;
+
 /**
- * Clone of Android's HexDump class, for use in debugging. Cosmetic changes
- * only.
+ * Clone of Android's /core/java/com/android/internal/util/HexDump class, for use in debugging.
+ * Changes: space separated hex strings
  */
 public class HexDump {
     private final static char[] HEX_DIGITS = {
             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
     };
 
+    private HexDump() {
+    }
+
     public static String dumpHexString(byte[] array) {
         return dumpHexString(array, 0, array.length);
     }
@@ -32,17 +37,12 @@ public class HexDump {
     public static String dumpHexString(byte[] array, int offset, int length) {
         StringBuilder result = new StringBuilder();
 
-        byte[] line = new byte[16];
+        byte[] line = new byte[8];
         int lineIndex = 0;
 
-        result.append("\n0x");
-        result.append(toHexString(offset));
-
         for (int i = offset; i < offset + length; i++) {
-            if (lineIndex == 16) {
-                result.append(" ");
-
-                for (int j = 0; j < 16; j++) {
+            if (lineIndex == line.length) {
+                for (int j = 0; j < line.length; j++) {
                     if (line[j] > ' ' && line[j] < '~') {
                         result.append(new String(line, j, 1));
                     } else {
@@ -50,32 +50,26 @@ public class HexDump {
                     }
                 }
 
-                result.append("\n0x");
-                result.append(toHexString(i));
+                result.append("\n");
                 lineIndex = 0;
             }
 
             byte b = array[i];
-            result.append(" ");
             result.append(HEX_DIGITS[(b >>> 4) & 0x0F]);
             result.append(HEX_DIGITS[b & 0x0F]);
+            result.append(" ");
 
             line[lineIndex++] = b;
         }
 
-        if (lineIndex != 16) {
-            int count = (16 - lineIndex) * 3;
-            count++;
-            for (int i = 0; i < count; i++) {
-                result.append(" ");
-            }
-
-            for (int i = 0; i < lineIndex; i++) {
-                if (line[i] > ' ' && line[i] < '~') {
-                    result.append(new String(line, i, 1));
-                } else {
-                    result.append(".");
-                }
+        for (int i = 0; i < (line.length - lineIndex); i++) {
+            result.append("   ");
+        }
+        for (int i = 0; i < lineIndex; i++) {
+            if (line[i] > ' ' && line[i] < '~') {
+                result.append(new String(line, i, 1));
+            } else {
+                result.append(".");
             }
         }
 
@@ -91,10 +85,12 @@ public class HexDump {
     }
 
     public static String toHexString(byte[] array, int offset, int length) {
-        char[] buf = new char[length * 2];
+        char[] buf = new char[length > 0 ? length * 3 - 1 : 0];
 
         int bufIndex = 0;
         for (int i = offset; i < offset + length; i++) {
+            if (i > offset)
+                buf[bufIndex++] = ' ';
             byte b = array[i];
             buf[bufIndex++] = HEX_DIGITS[(b >>> 4) & 0x0F];
             buf[bufIndex++] = HEX_DIGITS[b & 0x0F];
@@ -145,16 +141,16 @@ public class HexDump {
         if (c >= 'a' && c <= 'f')
             return (c - 'a' + 10);
 
-        throw new RuntimeException("Invalid hex char '" + c + "'");
+        throw new InvalidParameterException("Invalid hex char '" + c + "'");
     }
 
+    /** accepts any separator, e.g. space or newline */
     public static byte[] hexStringToByteArray(String hexString) {
         int length = hexString.length();
-        byte[] buffer = new byte[length / 2];
+        byte[] buffer = new byte[(length + 1) / 3];
 
-        for (int i = 0; i < length; i += 2) {
-            buffer[i / 2] = (byte) ((toByte(hexString.charAt(i)) << 4) | toByte(hexString
-                    .charAt(i + 1)));
+        for (int i = 0; i < length; i += 3) {
+            buffer[i / 3] = (byte) ((toByte(hexString.charAt(i)) << 4) | toByte(hexString.charAt(i + 1)));
         }
 
         return buffer;

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/MonotonicClock.java

@@ -0,0 +1,14 @@
+package com.hoho.android.usbserial.util;
+
+public final class MonotonicClock {
+
+    private static final long NS_PER_MS = 1_000_000;
+
+    private MonotonicClock() {
+    }
+
+    public static long millis() {
+        return System.nanoTime() / NS_PER_MS;
+    }
+
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java

@@ -1,93 +1,76 @@
 /* Copyright 2011-2013 Google Inc.
  * Copyright 2013 mike wakerly <opensource@hoho.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
- * USA.
- *
  * Project home page: https://github.com/mik3y/usb-serial-for-android
  */
 
 package com.hoho.android.usbserial.util;
 
-import android.hardware.usb.UsbRequest;
+import android.os.Process;
 import android.util.Log;
 
 import com.hoho.android.usbserial.driver.UsbSerialPort;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
- * Utility class which services a {@link UsbSerialPort} in its {@link #run()}
- * method.
+ * Utility class which services a {@link UsbSerialPort} in its {@link #runWrite()} ()} and {@link #runRead()} ()} ()} methods.
  *
  * @author mike wakerly (opensource@hoho.com)
  */
-public class SerialInputOutputManager implements Runnable {
+public class SerialInputOutputManager {
 
-    private static final String TAG = SerialInputOutputManager.class.getSimpleName();
-    private static final boolean DEBUG = true;
-
-    private static final int READ_WAIT_MILLIS = 200;
-    private static final int BUFSIZ = 4096;
-
-    private final UsbSerialPort mDriver;
-
-    private final ByteBuffer mReadBuffer = ByteBuffer.allocate(BUFSIZ);
-
-    // Synchronized by 'mWriteBuffer'
-    private final ByteBuffer mWriteBuffer = ByteBuffer.allocate(BUFSIZ);
-
-    private enum State {
+    public enum State {
         STOPPED,
+        STARTING,
         RUNNING,
         STOPPING
     }
 
-    // Synchronized by 'this'
-    private State mState = State.STOPPED;
+    public static boolean DEBUG = false;
 
-    // Synchronized by 'this'
-    private Listener mListener;
+    private static final String TAG = SerialInputOutputManager.class.getSimpleName();
+    private static final int BUFSIZ = 4096;
+
+    private int mReadTimeout = 0;
+    private int mWriteTimeout = 0;
+
+    private final Object mReadBufferLock = new Object();
+    private final Object mWriteBufferLock = new Object();
+
+    private ByteBuffer mReadBuffer; // default size = getReadEndpoint().getMaxPacketSize()
+    private ByteBuffer mWriteBuffer = ByteBuffer.allocate(BUFSIZ);
+
+    private int mThreadPriority = Process.THREAD_PRIORITY_URGENT_AUDIO;
+    private final AtomicReference<State> mState = new AtomicReference<>(State.STOPPED);
+    private CountDownLatch mStartuplatch = new CountDownLatch(2);
+    private Listener mListener; // Synchronized by 'this'
+    private final UsbSerialPort mSerialPort;
 
     public interface Listener {
         /**
          * Called when new incoming data is available.
          */
-        public void onNewData(byte[] data);
+        void onNewData(byte[] data);
 
         /**
-         * Called when {@link SerialInputOutputManager#run()} aborts due to an
-         * error.
+         * Called when {@link SerialInputOutputManager#runRead()} ()} or {@link SerialInputOutputManager#runWrite()} ()} ()} aborts due to an error.
          */
-        public void onRunError(Exception e);
+        void onRunError(Exception e);
     }
 
-    /**
-     * Creates a new instance with no listener.
-     */
-    public SerialInputOutputManager(UsbSerialPort driver) {
-        this(driver, null);
+    public SerialInputOutputManager(UsbSerialPort serialPort) {
+        mSerialPort = serialPort;
+        mReadBuffer = ByteBuffer.allocate(serialPort.getReadEndpoint().getMaxPacketSize());
     }
 
-    /**
-     * Creates a new instance with the provided listener.
-     */
-    public SerialInputOutputManager(UsbSerialPort driver, Listener listener) {
-        mDriver = driver;
+    public SerialInputOutputManager(UsbSerialPort serialPort, Listener listener) {
+        mSerialPort = serialPort;
         mListener = listener;
+        mReadBuffer = ByteBuffer.allocate(serialPort.getReadEndpoint().getMaxPacketSize());
     }
 
     public synchronized void setListener(Listener listener) {
@@ -98,91 +81,256 @@ public class SerialInputOutputManager implements Runnable {
         return mListener;
     }
 
-    public void writeAsync(byte[] data) {
-        synchronized (mWriteBuffer) {
-            mWriteBuffer.put(data);
+    /**
+     * setThreadPriority. By default a higher priority than UI thread is used to prevent data loss
+     *
+     * @param threadPriority  see {@link Process#setThreadPriority(int)}
+     * */
+    public void setThreadPriority(int threadPriority) {
+        if (!mState.compareAndSet(State.STOPPED, State.STOPPED)) {
+            throw new IllegalStateException("threadPriority only configurable before SerialInputOutputManager is started");
         }
-    }
-
-    public synchronized void stop() {
-        if (getState() == State.RUNNING) {
-            Log.i(TAG, "Stop requested");
-            mState = State.STOPPING;
-        }
-    }
-
-    private synchronized State getState() {
-        return mState;
+        mThreadPriority = threadPriority;
     }
 
     /**
-     * Continuously services the read and write buffers until {@link #stop()} is
-     * called, or until a driver exception is raised.
-     *
-     * NOTE(mikey): Uses inefficient read/write-with-timeout.
+     * read/write timeout
      */
-    @Override
-    public void run() {
-        synchronized (this) {
-            if (getState() != State.STOPPED) {
-                throw new IllegalStateException("Already running.");
-            }
-            mState = State.RUNNING;
-        }
+    public void setReadTimeout(int timeout) {
+        // when set if already running, read already blocks and the new value will not become effective now
+        if(mReadTimeout == 0 && timeout != 0 && mState.get() != State.STOPPED)
+            throw new IllegalStateException("readTimeout only configurable before SerialInputOutputManager is started");
+        mReadTimeout = timeout;
+    }
 
-        Log.i(TAG, "Running ..");
-        try {
-            while (true) {
-                if (getState() != State.RUNNING) {
-                    Log.i(TAG, "Stopping mState=" + getState());
-                    break;
-                }
-                step();
+    public int getReadTimeout() {
+        return mReadTimeout;
+    }
+
+    public void setWriteTimeout(int timeout) {
+        mWriteTimeout = timeout;
+    }
+
+    public int getWriteTimeout() {
+        return mWriteTimeout;
+    }
+
+    /**
+     * read/write buffer size
+     */
+    public void setReadBufferSize(int bufferSize) {
+        if (getReadBufferSize() == bufferSize)
+            return;
+        synchronized (mReadBufferLock) {
+            mReadBuffer = ByteBuffer.allocate(bufferSize);
+        }
+    }
+
+    public int getReadBufferSize() {
+        return mReadBuffer.capacity();
+    }
+
+    public void setWriteBufferSize(int bufferSize) {
+        if(getWriteBufferSize() == bufferSize)
+            return;
+        synchronized (mWriteBufferLock) {
+            ByteBuffer newWriteBuffer = ByteBuffer.allocate(bufferSize);
+            if(mWriteBuffer.position() > 0)
+                newWriteBuffer.put(mWriteBuffer.array(), 0, mWriteBuffer.position());
+            mWriteBuffer = newWriteBuffer;
+        }
+    }
+
+    public int getWriteBufferSize() {
+        return mWriteBuffer.capacity();
+    }
+
+    /**
+     * write data asynchronously
+     */
+    public void writeAsync(byte[] data) {
+        synchronized (mWriteBufferLock) {
+            mWriteBuffer.put(data);
+            mWriteBufferLock.notifyAll(); // Notify waiting threads
+        }
+    }
+
+    /**
+     * start SerialInputOutputManager in separate threads
+     */
+    public void start() {
+        if(mState.compareAndSet(State.STOPPED, State.STARTING)) {
+            mStartuplatch = new CountDownLatch(2);
+            new Thread(this::runRead, this.getClass().getSimpleName() + "_read").start();
+            new Thread(this::runWrite, this.getClass().getSimpleName() + "_write").start();
+            try {
+                mStartuplatch.await();
+                mState.set(State.RUNNING);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
             }
-        } catch (Exception e) {
-            Log.w(TAG, "Run ending due to exception: " + e.getMessage(), e);
-            final Listener listener = getListener();
-            if (listener != null) {
-              listener.onRunError(e);
+        } else {
+            throw new IllegalStateException("already started");
+        }
+    }
+
+    /**
+     * stop SerialInputOutputManager threads
+     *
+     * when using readTimeout == 0 (default), additionally use usbSerialPort.close() to
+     * interrupt blocking read
+     */
+    public void stop() {
+        if(mState.compareAndSet(State.RUNNING, State.STOPPING)) {
+            synchronized (mWriteBufferLock) {
+                mWriteBufferLock.notifyAll(); // wake up write thread to check the stop condition
             }
-        } finally {
-            synchronized (this) {
-                mState = State.STOPPED;
-                Log.i(TAG, "Stopped.");
+            Log.i(TAG, "Stop requested");
+        }
+    }
+
+    public State getState() {
+        return mState.get();
+    }
+
+    /**
+     * @return true if the thread is still running
+     */
+    private boolean isStillRunning() {
+        State state = mState.get();
+        return ((state == State.RUNNING) || (state == State.STARTING))
+            && !Thread.currentThread().isInterrupted();
+    }
+
+    /**
+     * Notify listener of an error
+     *
+     * @param e the exception
+     */
+    private void notifyErrorListener(Throwable e) {
+        Listener listener = getListener();
+        if (listener != null) {
+            try {
+                listener.onRunError(e instanceof Exception ? (Exception) e : new Exception(e));
+            } catch (Throwable t) {
+                Log.w(TAG, "Exception in onRunError: " + t.getMessage(), t);
             }
         }
     }
 
-    private void step() throws IOException {
+    /**
+     * Set the thread priority
+     */
+    private void setThreadPriority() {
+        if (mThreadPriority != Process.THREAD_PRIORITY_DEFAULT) {
+            Process.setThreadPriority(mThreadPriority);
+        }
+    }
+
+    /**
+     * Continuously services the read buffers until {@link #stop()} is called, or until a driver exception is
+     * raised.
+     */
+    void runRead() {
+        Log.i(TAG, "runRead running ...");
+        try {
+            setThreadPriority();
+            mStartuplatch.countDown();
+            do {
+                stepRead();
+            } while (isStillRunning());
+            Log.i(TAG, "runRead: Stopping mState=" + getState());
+        } catch (Throwable e) {
+            if (Thread.currentThread().isInterrupted()) {
+                Log.w(TAG, "runRead: interrupted");
+            } else if(mSerialPort.isOpen()) {
+                Log.w(TAG, "runRead ending due to exception: " + e.getMessage(), e);
+            } else {
+                Log.i(TAG, "runRead: Socket closed");
+            }
+            notifyErrorListener(e);
+        } finally {
+            if (mState.compareAndSet(State.RUNNING, State.STOPPING)) {
+                synchronized (mWriteBufferLock) {
+                    mWriteBufferLock.notifyAll(); // wake up write thread to check the stop condition
+                }
+            } else if (mState.compareAndSet(State.STOPPING, State.STOPPED)) {
+                Log.i(TAG, "runRead: Stopped mState=" + getState());
+            }
+        }
+    }
+
+    /**
+     * Continuously services the write buffers until {@link #stop()} is called, or until a driver exception is
+     * raised.
+     */
+    void runWrite() {
+        Log.i(TAG, "runWrite running ...");
+        try {
+            setThreadPriority();
+            mStartuplatch.countDown();
+            do {
+                stepWrite();
+            } while (isStillRunning());
+            Log.i(TAG, "runWrite: Stopping mState=" + getState());
+        } catch (Throwable e) {
+            if (Thread.currentThread().isInterrupted()) {
+                Log.w(TAG, "runWrite: interrupted");
+            } else if(mSerialPort.isOpen()) {
+                Log.w(TAG, "runWrite ending due to exception: " + e.getMessage(), e);
+            } else {
+                Log.i(TAG, "runWrite: Socket closed");
+            }
+            notifyErrorListener(e);
+        } finally {
+            if (!mState.compareAndSet(State.RUNNING, State.STOPPING)) {
+                if (mState.compareAndSet(State.STOPPING, State.STOPPED)) {
+                    Log.i(TAG, "runWrite: Stopped mState=" + getState());
+                }
+            }
+        }
+    }
+
+    private void stepRead() throws IOException {
         // Handle incoming data.
-        int len = mDriver.read(mReadBuffer.array(), READ_WAIT_MILLIS);
+        byte[] buffer;
+        synchronized (mReadBufferLock) {
+            buffer = mReadBuffer.array();
+        }
+        int len = mSerialPort.read(buffer, mReadTimeout);
         if (len > 0) {
-            if (DEBUG) Log.d(TAG, "Read data len=" + len);
+            if (DEBUG) {
+                Log.d(TAG, "Read data len=" + len);
+            }
             final Listener listener = getListener();
             if (listener != null) {
                 final byte[] data = new byte[len];
-                mReadBuffer.get(data, 0, len);
+                System.arraycopy(buffer, 0, data, 0, len);
                 listener.onNewData(data);
             }
-            mReadBuffer.clear();
         }
+    }
 
+    private void stepWrite() throws IOException, InterruptedException {
         // Handle outgoing data.
-        byte[] outBuff = null;
-        synchronized (mWriteBuffer) {
-            len = mWriteBuffer.position();
+        byte[] buffer = null;
+        synchronized (mWriteBufferLock) {
+            int len = mWriteBuffer.position();
             if (len > 0) {
-                outBuff = new byte[len];
+                buffer = new byte[len];
                 mWriteBuffer.rewind();
-                mWriteBuffer.get(outBuff, 0, len);
+                mWriteBuffer.get(buffer, 0, len);
                 mWriteBuffer.clear();
+                mWriteBufferLock.notifyAll(); // Notify writeAsync that there is space in the buffer
+            } else {
+                mWriteBufferLock.wait();
             }
         }
-        if (outBuff != null) {
+        if (buffer != null) {
             if (DEBUG) {
-                Log.d(TAG, "Writing data len=" + len);
+                Log.d(TAG, "Writing data len=" + buffer.length);
             }
-            mDriver.write(outBuff, READ_WAIT_MILLIS);
+            mSerialPort.write(buffer, mWriteTimeout);
         }
     }
 

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/UsbUtils.java

@@ -0,0 +1,33 @@
+package com.hoho.android.usbserial.util;
+
+import android.hardware.usb.UsbDeviceConnection;
+
+import java.util.ArrayList;
+
+public class UsbUtils {
+
+    private UsbUtils() {
+    }
+
+    public static  ArrayList<byte[]> getDescriptors(UsbDeviceConnection connection) {
+        ArrayList<byte[]> descriptors = new ArrayList<>();
+        byte[] rawDescriptors = connection.getRawDescriptors();
+        if (rawDescriptors != null) {
+            int pos = 0;
+            while (pos < rawDescriptors.length) {
+                int len = rawDescriptors[pos] & 0xFF;
+                if (len == 0)
+                    break;
+                if (pos + len > rawDescriptors.length)
+                    len = rawDescriptors.length - pos;
+                byte[] descriptor = new byte[len];
+                System.arraycopy(rawDescriptors, pos, descriptor, 0, len);
+                descriptors.add(descriptor);
+                pos += len;
+            }
+        }
+        return descriptors;
+    }
+
+
+}

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/XonXoffFilter.java

@@ -0,0 +1,47 @@
+package com.hoho.android.usbserial.util;
+
+import com.hoho.android.usbserial.driver.UsbSerialPort;
+
+import java.io.IOException;
+
+/**
+ * Some devices return XON and XOFF characters inline in read() data.
+ * Other devices return XON / XOFF condition thru getXOFF() method.
+ */
+
+public class XonXoffFilter {
+    private boolean xon = true;
+
+    public XonXoffFilter() {
+    }
+
+    public boolean getXON()  {
+        return xon;
+    }
+
+    /**
+     * Filter XON/XOFF from read() data and remember
+     *
+     * @param data unfiltered data
+     * @return filtered data
+     */
+    public byte[] filter(byte[] data) {
+        int found = 0;
+        for (int i=0; i<data.length; i++) {
+            if (data[i] == UsbSerialPort.CHAR_XON || data[i] == UsbSerialPort.CHAR_XOFF)
+                found++;
+        }
+        if(found == 0)
+            return data;
+        byte[] filtered = new byte[data.length - found];
+        for (int i=0, j=0; i<data.length; i++) {
+            if (data[i] == UsbSerialPort.CHAR_XON)
+                xon = true;
+            else if(data[i] == UsbSerialPort.CHAR_XOFF)
+                xon = false;
+            else
+                filtered[j++] = data[i];
+        }
+        return filtered;
+    }
+}

usbSerialForAndroid/src/test/java/android/util/Log.java

@@ -0,0 +1,29 @@
+// without this class Mockito complains about non-mocked Log methods
+package android.util;
+
+public class Log {
+    public static int d(String tag, String msg) {
+        System.out.println("DEBUG: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int i(String tag, String msg) {
+        System.out.println("INFO: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int w(String tag, String msg) {
+        System.out.println("WARN: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int w(String tag, String msg, Throwable tr) {
+        System.out.println("WARN: " + tag + ": " + msg + " / " + tr.getMessage());
+        return 0;
+    }
+
+    public static int e(String tag, String msg) {
+        System.out.println("ERROR: " + tag + ": " + msg);
+        return 0;
+    }
+}

usbSerialForAndroid/src/test/java/android/util/Pair.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+
+import androidx.annotation.Nullable;
+
+import java.util.Objects;
+
+/**
+ * Container to ease passing around a tuple of two objects. This object provides a sensible
+ * implementation of equals(), returning true if equals() is true on each of the contained
+ * objects.
+ */
+public class Pair<F, S> {
+    public final F first;
+    public final S second;
+
+    /**
+     * Constructor for a Pair.
+     *
+     * @param first the first object in the Pair
+     * @param second the second object in the pair
+     */
+    public Pair(F first, S second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    /**
+     * Checks the two objects for equality by delegating to their respective
+     * {@link Object#equals(Object)} methods.
+     *
+     * @param o the {@link Pair} to which this one is to be checked for equality
+     * @return true if the underlying objects of the Pair are both considered
+     *         equal
+     */
+    @Override
+    public boolean equals(@Nullable Object o) {
+        if (!(o instanceof Pair)) {
+            return false;
+        }
+        Pair<?, ?> p = (Pair<?, ?>) o;
+        return Objects.equals(p.first, first) && Objects.equals(p.second, second);
+    }
+
+    /**
+     * Compute a hash code using the hash codes of the underlying objects
+     *
+     * @return a hashcode of the Pair
+     */
+    @Override
+    public int hashCode() {
+        return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
+    }
+
+    @Override
+    public String toString() {
+        return "Pair{" + String.valueOf(first) + " " + String.valueOf(second) + "}";
+    }
+
+    /**
+     * Convenience method for creating an appropriately typed pair.
+     * @param a the first object in the Pair
+     * @param b the second object in the pair
+     * @return a Pair that is templatized with the types of a and b
+     */
+    public static <A, B> Pair <A, B> create(A a, B b) {
+        return new Pair<A, B>(a, b);
+    }
+}

usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriverTest.java

@@ -0,0 +1,546 @@
+package com.hoho.android.usbserial.driver;
+
+import static com.hoho.android.usbserial.driver.CdcAcmSerialDriver.USB_SUBCLASS_ACM;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.clearInvocations;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+
+import com.hoho.android.usbserial.util.HexDump;
+
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class CdcAcmSerialDriverTest {
+
+    @Test
+    public void standardDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        /*
+         * digispark - no IAD
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=null,mClass=2,mSubclass=2,mProtocol=1,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=8,mInterval=255]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=1,mAttributes=2,mMaxPacketSize=8,mInterval=0]
+         *     UsbEndpoint[mAddress=129,mAttributes=2,mMaxPacketSize=8,mInterval=0]]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 10 01 02 00 00 08 D0 16 7E 08 00 01 01 02 00 01\n" +
+                "09 02 43 00 02 01 00 80 32\n" +
+                "09 04 00 00 01 02 02 01 00\n" +
+                "05 24 00 10 01\n" +
+                "04 24 02 02\n" +
+                "05 24 06 00 01\n" +
+                "05 24 01 03 01\n" +
+                "07 05 83 03 08 00 FF\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 01 02 08 00 00\n" +
+                "07 05 81 02 08 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(2);
+        when(usbDevice.getInterface(0)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(dataInterface);
+        when(controlInterface.getId()).thenReturn(0);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getId()).thenReturn(1);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertEquals(driver.getClass(), probeDriver);
+    }
+
+    @Test
+    public void singleInterfaceDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface usbInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(usbInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(1);
+        when(usbDevice.getInterface(0)).thenReturn(usbInterface);
+        when(usbInterface.getEndpointCount()).thenReturn(3);
+        when(usbInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(usbInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(usbInterface.getEndpoint(2)).thenReturn(writeEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertNull(probeDriver);
+    }
+
+    @Test
+    public void multiPortDevice() throws Exception {
+        int n = 2;
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface[] controlInterfaces = new UsbInterface[n];
+        UsbInterface[] dataInterfaces = new UsbInterface[n];
+        UsbEndpoint[] controlEndpoints = new UsbEndpoint[n];
+        UsbEndpoint[] readEndpoints = new UsbEndpoint[n];
+        UsbEndpoint[] writeEndpoints = new UsbEndpoint[n];
+
+        /*
+         * pi zero - dual port
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=TinyUSB CDC,mClass=2,mSubclass=2,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=129,mAttributes=3,mMaxPacketSize=8,mInterval=16]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=2,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=130,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=2,mAlternateSetting=0,mName=TinyUSB CDC,mClass=2,mSubclass=2,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=8,mInterval=16]]
+         *   UsbInterface[mId=3,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=4,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *      UsbEndpoint[mAddress=132,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 8D 00 04 01 00 80 32\n" +
+                "08 0B 00 02 02 02 00 00\n" +
+                "09 04 00 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 01\n" +
+                "04 24 02 02\n" +
+                "05 24 06 00 01\n" +
+                "07 05 81 03 08 00 10\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00\n"));
+        when(usbDevice.getInterfaceCount()).thenReturn(2*n);
+        for(int i=0; i<n; i++) {
+            controlInterfaces[i] = mock(UsbInterface.class);
+            dataInterfaces[i] = mock(UsbInterface.class);
+            controlEndpoints[i] = mock(UsbEndpoint.class);
+            readEndpoints[i] = mock(UsbEndpoint.class);
+            writeEndpoints[i] = mock(UsbEndpoint.class);
+            when(usbDeviceConnection.claimInterface(controlInterfaces[i], true)).thenReturn(true);
+            when(usbDeviceConnection.claimInterface(dataInterfaces[i], true)).thenReturn(true);
+            when(usbDevice.getInterface(2*i  )).thenReturn(controlInterfaces[i]);
+            when(usbDevice.getInterface(2*i+1)).thenReturn(dataInterfaces[i]);
+            when(controlInterfaces[i].getId()).thenReturn(2*i);
+            when(controlInterfaces[i].getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+            when(controlInterfaces[i].getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+            when(controlInterfaces[i].getEndpointCount()).thenReturn(1);
+            when(controlInterfaces[i].getEndpoint(0)).thenReturn(controlEndpoints[i]);
+            when(dataInterfaces[i].getId()).thenReturn(2*i+1);
+            when(dataInterfaces[i].getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+            when(dataInterfaces[i].getEndpointCount()).thenReturn(2);
+            when(dataInterfaces[i].getEndpoint(0)).thenReturn(writeEndpoints[i]);
+            when(dataInterfaces[i].getEndpoint(1)).thenReturn(readEndpoints[i]);
+            when(controlEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+            when(controlEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+            when(readEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+            when(readEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+            when(writeEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+            when(writeEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        }
+        int i = 1;
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(i);
+        port.mConnection = usbDeviceConnection;
+        // reset invocations from countPorts()
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        port.openInt();
+        assertEquals(readEndpoints[i], port.mReadEndpoint);
+        assertEquals(writeEndpoints[i], port.mWriteEndpoint);
+        verify(controlInterfaces[0], times(0)).getInterfaceClass(); // not openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with IAD
+        port.closeInt();
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(null);
+        port.openInt();
+        verify(controlInterfaces[0], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        port.closeInt();
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray("01 02 02 82 02")); // truncated descriptor
+        port.openInt();
+        verify(controlInterfaces[0], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+    }
+
+    @Test
+    public void compositeDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface massStorageInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbInterface hidInterface = mock(UsbInterface.class);
+        UsbInterface vendorInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        /*
+         * BBC micro:bit
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=USB_MSC,mClass=8,mSubclass=6,mProtocol=80,mEndpoints=[
+         *     UsbEndpoint[mAddress=130,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=2,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=mbed Serial Port,mClass=2,mSubclass=2,mProtocol=1,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=16,mInterval=32]]
+         *   UsbInterface[mId=2,mAlternateSetting=0,mName=mbed Serial Port,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=4,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=132,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=3,mAlternateSetting=0,mName=CMSIS-DAP,mClass=3,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=129,mAttributes=3,mMaxPacketSize=64,mInterval=1]
+         *     UsbEndpoint[mAddress=1,mAttributes=3,mMaxPacketSize=64,mInterval=1]]
+         *   UsbInterface[mId=4,mAlternateSetting=0,mName=WebUSB: CMSIS-DAP,mClass=255,mSubclass=3,mProtocol=0,mEndpoints=[]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 10 02 EF 02 01 40 28 0D 04 02 00 10 01 02 03 01\n" +
+                "09 02 8B 00 05 01 00 80 FA\n" +
+                "09 04 00 00 02 08 06 50 08\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 01 02 02 02 01 04\n" +
+                "09 04 01 00 01 02 02 01 04\n" +
+                "05 24 00 10 01\n" +
+                "05 24 01 03 02\n" +
+                "04 24 02 06\n" +
+                "05 24 06 01 02\n" +
+                "07 05 83 03 10 00 20\n" +
+                "09 04 02 00 02 0A 00 00 05\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00\n" +
+                "09 04 03 00 02 03 00 00 06\n" +
+                "09 21 00 01 00 01 22 21 00\n" +
+                "07 05 81 03 40 00 01\n" +
+                "07 05 01 03 40 00 01\n" +
+                "09 04 04 00 00 FF 03 00 07"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(5);
+        when(usbDevice.getInterface(0)).thenReturn(massStorageInterface);
+        when(usbDevice.getInterface(1)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(2)).thenReturn(dataInterface);
+        when(usbDevice.getInterface(3)).thenReturn(hidInterface);
+        when(usbDevice.getInterface(4)).thenReturn(vendorInterface);
+        when(massStorageInterface.getId()).thenReturn(0);
+        when(massStorageInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_MASS_STORAGE);
+        when(controlInterface.getId()).thenReturn(1);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(2);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(hidInterface.getId()).thenReturn(3);
+        when(hidInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_HID);
+        when(vendorInterface.getId()).thenReturn(4);
+        when(vendorInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_VENDOR_SPEC);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertEquals(driver.getClass(), probeDriver);
+    }
+
+    @Test
+    public void compositeRndisDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface rndisControlInterface = mock(UsbInterface.class);
+        UsbInterface rndisDataInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        // has multiple USB_CLASS_CDC_DATA interfaces => get correct with IAD
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 8D 00 04 01 00 80 32\n" +
+                "08 0B 00 02 E0 01 03 00\n" +
+                "09 04 00 00 01 E0 01 03 04\n" +
+                "05 24 00 10 01\n" +
+                "05 24 01 00 01\n" +
+                "04 24 02 00\n" +
+                "05 24 06 00 01\n" +
+                "07 05 81 03 08 00 01\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(4);
+        when(usbDevice.getInterface(0)).thenReturn(rndisControlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(rndisDataInterface);
+        when(usbDevice.getInterface(2)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(3)).thenReturn(dataInterface);
+        when(rndisControlInterface.getId()).thenReturn(0);
+        when(rndisControlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_WIRELESS_CONTROLLER);
+        when(rndisControlInterface.getInterfaceSubclass()).thenReturn(1);
+        when(rndisControlInterface.getInterfaceProtocol()).thenReturn(3);
+        when(rndisDataInterface.getId()).thenReturn(1);
+        when(rndisDataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(controlInterface.getId()).thenReturn(2);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(3);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+    }
+
+    @Test
+    public void compositeAlternateSettingDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface ethernetControlInterface = mock(UsbInterface.class);
+        UsbInterface ethernetDummyInterface = mock(UsbInterface.class);
+        UsbInterface ethernetDataInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        // has multiple USB_CLASS_CDC_DATA interfaces => get correct with IAD
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 9A 00 04 01 00 80 32\n" +
+                "08 0B 00 02 02 06 00 00\n" +
+                "09 04 00 00 01 02 06 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 06 00 01\n" +
+                "0D 24 0F 04 00 00 00 00 DC 05 00 00 00\n" +
+                "07 05 81 03 08 00 01\n" +
+                "09 04 01 00 00 0A 00 00 00\n" +
+                "09 04 01 01 02 0A 00 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(5);
+        when(usbDevice.getInterface(0)).thenReturn(ethernetControlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(ethernetDummyInterface);
+        when(usbDevice.getInterface(2)).thenReturn(ethernetDataInterface);
+        when(usbDevice.getInterface(3)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(4)).thenReturn(dataInterface);
+        when(ethernetControlInterface.getId()).thenReturn(0);
+        when(ethernetControlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(ethernetControlInterface.getInterfaceSubclass()).thenReturn(6);
+        when(ethernetDummyInterface.getId()).thenReturn(1);
+        when(ethernetDummyInterface.getAlternateSetting()).thenReturn(0);
+        when(ethernetDummyInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(ethernetDataInterface.getId()).thenReturn(1);
+        when(ethernetDataInterface.getAlternateSetting()).thenReturn(1);
+        when(ethernetDataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(controlInterface.getId()).thenReturn(2);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(3);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+    }
+
+    @Test
+    public void invalidStandardDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(2);
+        when(usbDevice.getInterface(0)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(dataInterface);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        //when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        //when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        assertThrows(IOException.class, port::openInt);
+    }
+
+    @Test
+    public void invalidSingleInterfaceDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface usbInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        //UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(usbInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(1);
+        when(usbDevice.getInterface(0)).thenReturn(usbInterface);
+        when(usbInterface.getEndpointCount()).thenReturn(2);
+        when(usbInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(usbInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        //when(usbInterface.getEndpoint(2)).thenReturn(writeEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        //when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        //when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertNull(port.mWriteEndpoint);
+    }
+
+}

usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/driver/FtdiSerialDriverTest.java

@@ -0,0 +1,89 @@
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class FtdiSerialDriverTest {
+
+    private final UsbDevice usbDevice = mock(UsbDevice.class);
+    private final UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+
+    private void initBuf(byte[] buf) {
+        for(int i=0; i<buf.length; i++)
+            buf[i] = (byte) i;
+    }
+    private boolean testBuf(byte[] buf, int len) {
+        byte j = 2;
+        for(int i=0; i<len; i++) {
+            if(buf[i]!=j)
+                return false;
+            j++;
+            if(j % 64 == 0)
+                j+=2;
+        }
+        return true;
+    }
+
+    @Test
+    public void readFilter() throws Exception {
+        byte[] buf = new byte[2048];
+        int len;
+
+        when(usbDevice.getInterfaceCount()).thenReturn(1);
+        when(readEndpoint.getMaxPacketSize()).thenReturn(64);
+        FtdiSerialDriver driver = new FtdiSerialDriver(usbDevice);
+        FtdiSerialDriver.FtdiSerialPort port = (FtdiSerialDriver.FtdiSerialPort) driver.getPorts().get(0);
+        port.mReadEndpoint = readEndpoint;
+
+        len = port.readFilter(buf, 0);
+        assertEquals(len, 0);
+
+        assertThrows(IOException.class, () -> port.readFilter(buf, 1));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 2);
+        assertEquals(len, 0);
+
+        initBuf(buf);
+        len = port.readFilter(buf, 3);
+        assertEquals(len, 1);
+        assertTrue(testBuf(buf, len));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 4);
+        assertEquals(len, 2);
+        assertTrue(testBuf(buf, len));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 64);
+        assertEquals(len, 62);
+        assertTrue(testBuf(buf, len));
+
+        assertThrows(IOException.class, () -> port.readFilter(buf, 65));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 66);
+        assertEquals(len, 62);
+        assertTrue(testBuf(buf, len));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 68);
+        assertEquals(len, 64);
+        assertTrue(testBuf(buf, len));
+
+        initBuf(buf);
+        len = port.readFilter(buf, 16*64+11);
+        assertEquals(len, 16*62+9);
+        assertTrue(testBuf(buf, len));
+    }
+}

usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/util/HexDumpText.java

@@ -0,0 +1,44 @@
+package com.hoho.android.usbserial.util;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+
+import org.junit.Test;
+
+import java.security.InvalidParameterException;
+
+public class HexDumpText {
+
+    @Test
+    public void toByteArray() throws Exception {
+        assertThat(HexDump.toByteArray((byte)0x4a), equalTo(new byte[]{ 0x4A}));
+        assertThat(HexDump.toByteArray((short)0x4a5b), equalTo(new byte[]{ 0x4A, 0x5B}));
+        assertThat(HexDump.toByteArray((int)0x4a5b6c7d), equalTo(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+    }
+
+    @Test
+    public void toHexString() throws Exception {
+        assertEquals("4A", HexDump.toHexString((byte)0x4a));
+        assertEquals("4A 5B", HexDump.toHexString((short)0x4a5b));
+        assertEquals("4A 5B 6C 7D", HexDump.toHexString((int)0x4a5b6c7d));
+        assertEquals("4A 5B 6C 7D", HexDump.toHexString(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+        assertEquals("5B 6C", HexDump.toHexString(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}, 1, 2));
+    }
+
+    @Test
+    public void dumpHexString() throws Exception {
+        assertEquals("10 31 32 33 34 35 36 37 .1234567\n18 39                   .9", HexDump.dumpHexString(new byte[]{ 0x10, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x18, 0x39}));
+        assertEquals("31 32                   12", HexDump.dumpHexString(new byte[]{ 0x30, 0x31, 0x32, 0x33}, 1, 2));
+    }
+
+    @Test
+    public void toByte() throws Exception {
+        assertThat(HexDump.hexStringToByteArray("4a 5B-6c\n7d"), equalTo(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3 "));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3z"));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3Z"));
+    }
+
+}

usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/util/SerialInputOutputManagerTest.java

@@ -0,0 +1,55 @@
+package com.hoho.android.usbserial.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import android.hardware.usb.UsbEndpoint;
+import android.os.Process;
+
+import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
+
+import org.junit.Test;
+
+public class SerialInputOutputManagerTest {
+
+
+    // catch all Throwables in onNewData() and onRunError()
+    @Test
+    public void throwable() throws Exception {
+
+        class ExceptionListener implements SerialInputOutputManager.Listener {
+            public Exception e;
+            @Override public void onNewData(byte[] data) { throw new RuntimeException("exception1"); }
+            @Override public void onRunError(Exception e) { this.e = e; throw new RuntimeException("exception2"); }
+        }
+        class ErrorListener implements SerialInputOutputManager.Listener {
+            public Exception e;
+            @Override public void onNewData(byte[] data) { throw new UnknownError("error1"); }
+            @Override public void onRunError(Exception e) { this.e = e; throw new UnknownError("error2");}
+        }
+
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        when(readEndpoint.getMaxPacketSize()).thenReturn(16);
+        CommonUsbSerialPort port = mock(CommonUsbSerialPort.class);
+        when(port.getReadEndpoint()).thenReturn(readEndpoint);
+        when(port.read(new byte[16], 0)).thenReturn(1);
+        when(port.isOpen()).thenReturn(true);
+        SerialInputOutputManager manager = new SerialInputOutputManager(port);
+        manager.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT);
+
+        ExceptionListener exceptionListener = new ExceptionListener();
+        manager.setListener(exceptionListener);
+        manager.runRead();
+        assertEquals(RuntimeException.class, exceptionListener.e.getClass());
+        assertEquals("exception1", exceptionListener.e.getMessage());
+
+        ErrorListener errorListener = new ErrorListener();
+        manager.setListener(errorListener);
+        manager.runRead();
+        assertEquals(Exception.class, errorListener.e.getClass());
+        assertEquals("java.lang.UnknownError: error1", errorListener.e.getMessage());
+        assertEquals(UnknownError.class, errorListener.e.getCause().getClass());
+        assertEquals("error1", errorListener.e.getCause().getMessage());
+    }
+}