new setBreak() method

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

@@ -141,6 +141,25 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
         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);
         }

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

@@ -6,4 +6,8 @@
         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>

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

@@ -1740,6 +1740,30 @@ public class DeviceTest {
         }
     }
 
+    @Test
+    public void setBreak() throws Exception {
+        usb.open();
+        telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
+        doReadWrite("");
+        usb.serialPort.setBreak(true);
+        Thread.sleep(100);
+        usb.serialPort.setBreak(false);
+        // RFC2217 has SET_CONTROL + REQ_BREAK_STATE request, but this is not supported by pyserial
+        // as there is no easy notification on <break> condition. By default break is returned as
+        // 0 byte on Linux, see https://man7.org/linux/man-pages/man3/termios.3.html -> BRKINT
+        byte[] data = telnet.read(1);
+        if (usb.serialDriver instanceof CdcAcmSerialDriver) {
+            // BREAK forwarding not implemented by arduino_leonardo_bridge.ino
+            assertThat("<break>", data, equalTo(new byte[]{}));
+        } else if(isCp21xxRestrictedPort) {
+            assertThat("<break>", data, equalTo(new byte[]{0x26})); // send the last byte again?
+        } else {
+            assertThat("<break>", data, equalTo(new byte[]{0}));
+        }
+        doReadWrite("");
+    }
+
     @Test
     public void deviceConnection() throws Exception {
         byte[] buf = new byte[256];
@@ -1813,6 +1837,11 @@ public class DeviceTest {
             } catch (IOException ignored) {
             }
         }
+        try {
+            usb.serialPort.setBreak(true);
+            fail("setBreak error expected");
+        } catch (IOException ignored) {
+        }
         usb.close();
         try {
             usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD, UsbWrapper.OpenCloseFlags.NO_DEVICE_CONNECTION));

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

@@ -278,6 +278,12 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
         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);
+        }
+
     }
 
     public static Map<Integer, int[]> getSupportedDevices() {

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

@@ -341,6 +341,25 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 		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");
+			}
+		}
 	}
 
 	public static Map<Integer, int[]> getSupportedDevices() {

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

@@ -264,4 +264,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
         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

@@ -59,6 +59,7 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
          */
         private static final int SILABSER_IFC_ENABLE_REQUEST_CODE = 0x00;
         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_FLUSH_REQUEST_CODE = 0x12;
@@ -314,6 +315,10 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
             }
         }
 
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            setConfigSingle(SILABSER_SET_BREAK_REQUEST_CODE, value ? 1 : 0);
+        }
     }
 
     public static Map<Integer, int[]> getSupportedDevices() {

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

@@ -84,6 +84,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
         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);
@@ -280,6 +281,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
             if (result != 0) {
                 throw new IOException("Setting parameters failed: result=" + result);
             }
+            breakConfig = config;
         }
 
         private int getStatus() throws IOException {
@@ -366,7 +368,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                 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("purge write buffer failed: result=" + result);
+                    throw new IOException("Purge write buffer failed: result=" + result);
                 }
             }
 
@@ -374,11 +376,22 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                 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("purge read buffer failed: result=" + result);
+                    throw new IOException("Purge read buffer failed: result=" + result);
                 }
             }
         }
 
+        @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);

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

@@ -77,6 +77,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
         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_REQUEST = 0x87;
         private static final int STATUS_NOTIFICATION = 0xa1; // similar to CDC SERIAL_STATE but different length
 
@@ -492,6 +493,11 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                 vendorOut(FLUSH_TX_REQUEST, 0, null);
             }
         }
+
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            ctrlOut(SEND_BREAK_REQUEST, value ? 0xffff : 0, 0, null);
+        }
     }
 
     public static Map<Integer, int[]> getSupportedDevices() {

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

@@ -248,6 +248,13 @@ public interface UsbSerialPort extends Closeable {
      */
     public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException;
 
+    /**
+     * send BREAK condition.
+     *
+     * @param value set/reset
+     */
+    public void setBreak(boolean value) throws IOException;
+
     /**
      * Returns the current state of the connection.
      */