PL2303(HX) support non-standard baud rates

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

@@ -302,8 +302,25 @@ public class DeviceTest {
                 28800, 38400, 57600, 115200, 128000, 134400, 161280, 201600, 230400, 268800,
                 403200, 460800, 614400, 806400, 921600, 1228800, 2457600, 3000000, /*6000000*/
         };
-        for(int baudRate : baudRates) {
         usb.open();
+
+        try {
+            usb.setParameters(45, 8, 1, UsbSerialPort.PARITY_NONE);
+            fail("baud rate to low expected");
+        } catch(UnsupportedOperationException ignored) {}
+        usb.setParameters(46, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb.setParameters(384_000_000, 8, 1, UsbSerialPort.PARITY_NONE);
+        try {
+            usb.setParameters(384_000_001, 8, 1, UsbSerialPort.PARITY_NONE);
+            fail("baud rate to high expected");
+        } catch(UnsupportedOperationException ignored) {}
+        usb.setParameters(11_636_363, 8, 1, UsbSerialPort.PARITY_NONE);
+        try {
+            usb.setParameters(11_636_364, 8, 1, UsbSerialPort.PARITY_NONE);
+            fail("baud rate deviation to high expected");
+        } catch(UnsupportedOperationException ignored) {}
+
+        for(int baudRate : baudRates) {
             int readWait = 500;
             if(baudRate < 300) readWait = 1000;
             if(baudRate < 150) readWait = 2000;
@@ -311,40 +328,31 @@ public class DeviceTest {
             usb.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
             doReadWrite(String.valueOf(baudRate), readWait);
 
-            try {
             usb.setParameters(baudRate + 1, 8, 1, UsbSerialPort.PARITY_NONE);
-                fail("unsupported baud rate error expected "+baudRate);
+            doReadWrite(String.valueOf(baudRate + 1), readWait);
-            } catch(UnsupportedOperationException ignored) {}
-
-            usb.setParameters(baudRate + (1<<29), 8, 1, UsbSerialPort.PARITY_NONE);
-            doReadWrite(String.valueOf(baudRate) + " + 1<<29", readWait);
 
             // silent fallback to 9600 for unsupported baud rates
             telnet.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
             usb.setParameters(baudRate + 1 + (1<<29), 8, 1, UsbSerialPort.PARITY_NONE);
             doReadWrite(String.valueOf(baudRate + 1) + " + 1<<29", readWait);
-            usb.close();
         }
 
         // some PL2303... data sheets mention additional baud rates, others don't
         // they do not work with my devices and linux driver also excludes them
-        usb.open();
-        telnet.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
         baudRates = new int[]{110, 56000, 256000};
         for(int baudRate : baudRates) {
             int readWait = 500;
             if(baudRate < 300) readWait = 1000;
             if(baudRate < 150) readWait = 2000;
-            try {
+            telnet.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
             usb.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
-                fail("unsupported baud rate error expected "+baudRate);
+            doReadWrite(String.valueOf(baudRate), readWait);
-            } catch(UnsupportedOperationException ignored) {}
 
             // silent fallback to 9600 for unsupported baud rates
+            telnet.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
             usb.setParameters(baudRate + (1<<29), 8, 1, UsbSerialPort.PARITY_NONE);
             doReadWrite(String.valueOf(baudRate ) + " + 1<<29", readWait);
         }
-        usb.close();
     }
 
     @Test
@@ -460,12 +468,6 @@ public class DeviceTest {
             doReadWrite(baudRate+"/8N1");
         }
         if(rfc2217_server_nonstandard_baudrates && !isCp21xxRestrictedPort) {
-            if (usb.serialDriver instanceof ProlificSerialDriver) {
-                try {
-                    usb.setParameters(42000, 8, 1, UsbSerialPort.PARITY_NONE);
-                    fail("unsupported baud rate error expected");
-                } catch (UnsupportedOperationException ignored) {}
-            } else {
             usb.setParameters(42000, 8, 1, UsbSerialPort.PARITY_NONE);
             telnet.setParameters(42000, 8, 1, UsbSerialPort.PARITY_NONE);
 
@@ -491,7 +493,6 @@ public class DeviceTest {
                 assertThat("42000/8N1", data2, equalTo(buf2));
             }
         }
-        }
         { // non matching baud rate
             telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
             usb.setParameters(2400, 8, 1, UsbSerialPort.PARITY_NONE);

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

@@ -176,7 +176,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
         private void setBaudrate(int baudRate) throws IOException {
             int divisor, subdivisor, effectiveBaudRate;
             if (baudRate > 3500000) {
-                throw new IOException("Baud rate to high");
+                throw new UnsupportedOperationException("Baud rate to high");
             } else if(baudRate >= 2500000) {
                 divisor = 0;
                 subdivisor = 0;
@@ -191,13 +191,13 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                 subdivisor = divisor & 0x07;
                 divisor >>= 3;
                 if (divisor > 0x3fff) // exceeds bit 13 at 183 baud
-                    throw new IOException("Baud rate to low");
+                    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 IOException(String.format("baud rate deviation %.1f%% is higher than allowed 3%%", baudRateError*100));
+                throw new UnsupportedOperationException(String.format("Baud rate deviation %.1f%% is higher than allowed 3%%", baudRateError*100));
             int value = divisor;
             int index = 0;
             switch(subdivisor) {

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

@@ -19,6 +19,7 @@ import android.util.Log;
 import com.hoho.android.usbserial.BuildConfig;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.LinkedHashMap;
@@ -34,7 +35,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             28800, 38400, 57600, 115200, 128000, 134400, 161280, 201600, 230400, 268800,
             403200, 460800, 614400, 806400, 921600, 1228800, 2457600, 3000000, 6000000
     };
-
+    private enum DeviceType { DEVICE_TYPE_01, DEVICE_TYPE_HX};
 
     private final UsbDevice mDevice;
     private final UsbSerialPort mPort;
@@ -89,11 +90,7 @@ 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 DeviceType mDeviceType = DeviceType.DEVICE_TYPE_HX;
-        private static final int DEVICE_TYPE_0 = 1;
-        private static final int DEVICE_TYPE_1 = 2;
-
-        private int mDeviceType = DEVICE_TYPE_HX;
         private UsbEndpoint mInterruptEndpoint;
         private int mControlLinesValue = 0;
         private int mBaudRate = -1, mDataBits = -1, mStopBits = -1, mParity = -1;
@@ -172,7 +169,7 @@ 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_HX) ? 0x44 : 0x24, null);
         }
 
         private void setControlLines(int newControlLinesValue) throws IOException {
@@ -272,22 +269,22 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             }
 
             if (mDevice.getDeviceClass() == 0x02) {
-                mDeviceType = DEVICE_TYPE_0;
+                mDeviceType = DeviceType.DEVICE_TYPE_01;
             } else {
                 byte[] rawDescriptors = connection.getRawDescriptors();
                 if(rawDescriptors == null || rawDescriptors.length <8) {
                     Log.w(TAG, "Could not get device descriptors, Assuming that it is a HX device");
-                    mDeviceType = DEVICE_TYPE_HX;
+                    mDeviceType = DeviceType.DEVICE_TYPE_HX;
                 } else {
                     byte maxPacketSize0 = rawDescriptors[7];
                     if (maxPacketSize0 == 64) {
-                        mDeviceType = DEVICE_TYPE_HX;
+                        mDeviceType = DeviceType.DEVICE_TYPE_HX;
                     } else if ((mDevice.getDeviceClass() == 0x00)
                             || (mDevice.getDeviceClass() == 0xff)) {
-                        mDeviceType = DEVICE_TYPE_1;
+                        mDeviceType = DeviceType.DEVICE_TYPE_01;
                     } else {
                         Log.w(TAG, "Could not detect PL2303 subtype, Assuming that it is a HX device");
-                        mDeviceType = DEVICE_TYPE_HX;
+                        mDeviceType = DeviceType.DEVICE_TYPE_HX;
                     }
                 }
             }
@@ -328,7 +325,40 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                     return baudRate;
                 }
             }
-            throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
+            /*
+             * Formula taken from Linux + FreeBSD.
+             *   baudrate = baseline / (mantissa * 4^exponent)
+             * where
+             *   mantissa = buf[8:0]
+             *   exponent = buf[11:9]
+             *
+             * Note: The formula does not work for all PL2303 variants.
+             *       Ok for PL2303HX. Not ok for PL2303TA. Other variants unknown.
+             */
+            int baseline, mantissa, exponent;
+            baseline = 12000000 * 32;
+            mantissa = baseline / baudRate;
+            if (mantissa == 0) { // > unrealistic 384 MBaud
+                throw new UnsupportedOperationException("Baud rate to high");
+            }
+            exponent = 0;
+            while (mantissa >= 512) {
+                if (exponent < 7) {
+                    mantissa >>= 2;	/* divide by 4 */
+                    exponent++;
+                } else { // < 45.8 baud
+                    throw new UnsupportedOperationException("Baud rate to low");
+                }
+            }
+            int effectiveBaudRate = (baseline / mantissa) >> (exponent << 1);
+            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));
+            int buf = mantissa + (exponent<<9) + (1<<31);
+
+            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