Add ability for user to specify whether RTS is high/low when sending in RS485 mode

src/main/c/Android/jni/SerialPort_Android.c

@@ -2,7 +2,7 @@
  * SerialPort_Android.c
  *
  *       Created on:  Mar 13, 2015
- *  Last Updated on:  Nov 12, 2019
+ *  Last Updated on:  Jan 21, 2020
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2020 Fazecast, Inc.
@@ -67,6 +67,7 @@ jfieldID flowControlField;
 jfieldID sendDeviceQueueSizeField;
 jfieldID receiveDeviceQueueSizeField;
 jfieldID rs485ModeField;
+jfieldID rs485ActiveHighField;
 jfieldID rs485DelayBeforeField;
 jfieldID rs485DelayAfterField;
 jfieldID timeoutModeField;
@@ -125,6 +126,7 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_initializeLibrar
 	sendDeviceQueueSizeField = (*env)->GetFieldID(env, serialCommClass, "sendDeviceQueueSize", "I");
 	receiveDeviceQueueSizeField = (*env)->GetFieldID(env, serialCommClass, "receiveDeviceQueueSize", "I");
 	rs485ModeField = (*env)->GetFieldID(env, serialCommClass, "rs485Mode", "Z");
+	rs485ActiveHighField = (*env)->GetFieldID(env, serialCommClass, "rs485ActiveHigh", "Z");
 	rs485DelayBeforeField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayBefore", "I");
 	rs485DelayAfterField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayAfter", "I");
 	timeoutModeField = (*env)->GetFieldID(env, serialCommClass, "timeoutMode", "I");
@@ -203,6 +205,7 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	int rs485DelayAfter = (*env)->GetIntField(env, obj, rs485DelayAfterField);
 	unsigned char configDisabled = (*env)->GetBooleanField(env, obj, disableConfigField);
 	unsigned char rs485ModeEnabled = (*env)->GetBooleanField(env, obj, rs485ModeField);
+	unsigned char rs485ActiveHigh = (*env)->GetBooleanField(env, obj, rs485ActiveHighField);
 	unsigned char isDtrEnabled = (*env)->GetBooleanField(env, obj, isDtrEnabledField);
 	unsigned char isRtsEnabled = (*env)->GetBooleanField(env, obj, isRtsEnabledField);
 	tcflag_t byteSize = (byteSizeInt == 5) ? CS5 : (byteSizeInt == 6) ? CS6 : (byteSizeInt == 7) ? CS7 : CS8;
@@ -271,9 +274,19 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	if (ioctl(serialPortFD, TIOCGRS485, &rs485Conf) == 0)
 	{
 		if (rs485ModeEnabled)
-			rs485Conf.flags |= SER_RS485_ENABLED; // Set these too? SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND
+			rs485Conf.flags |= SER_RS485_ENABLED;
 		else
-			rs485Conf.flags &= ~SER_RS485_ENABLED; // Clear these too? &= ~(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND);
+			rs485Conf.flags &= ~SER_RS485_ENABLED;
+		if (rs485ActiveHigh)
+		{
+			rs485Conf.flags |= SER_RS485_RTS_ON_SEND;
+			rs485Conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
+		}
+		else
+		{
+			rs485Conf.flags &= ~(SER_RS485_RTS_ON_SEND);
+			rs485Conf.flags |= SER_RS485_RTS_AFTER_SEND;
+		}
 		rs485Conf.delay_rts_before_send = rs485DelayBefore;
 		rs485Conf.delay_rts_after_send = rs485DelayAfter;
 		ioctl(serialPortFD, TIOCSRS485, &rs485Conf);

src/main/c/Posix/SerialPort_Posix.c

@@ -2,7 +2,7 @@
  * SerialPort_Posix.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Nov 12, 2019
+ *  Last Updated on:  Jan 21, 2020
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2020 Fazecast, Inc.
@@ -65,6 +65,7 @@ jfieldID flowControlField;
 jfieldID sendDeviceQueueSizeField;
 jfieldID receiveDeviceQueueSizeField;
 jfieldID rs485ModeField;
+jfieldID rs485ActiveHighField;
 jfieldID rs485DelayBeforeField;
 jfieldID rs485DelayAfterField;
 jfieldID timeoutModeField;
@@ -229,6 +230,7 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_initializeLibrar
 	sendDeviceQueueSizeField = (*env)->GetFieldID(env, serialCommClass, "sendDeviceQueueSize", "I");
 	receiveDeviceQueueSizeField = (*env)->GetFieldID(env, serialCommClass, "receiveDeviceQueueSize", "I");
 	rs485ModeField = (*env)->GetFieldID(env, serialCommClass, "rs485Mode", "Z");
+	rs485ActiveHighField = (*env)->GetFieldID(env, serialCommClass, "rs485ActiveHigh", "Z");
 	rs485DelayBeforeField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayBefore", "I");
 	rs485DelayAfterField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayAfter", "I");
 	timeoutModeField = (*env)->GetFieldID(env, serialCommClass, "timeoutMode", "I");
@@ -317,6 +319,7 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	int rs485DelayAfter = (*env)->GetIntField(env, obj, rs485DelayAfterField);
 	unsigned char configDisabled = (*env)->GetBooleanField(env, obj, disableConfigField);
 	unsigned char rs485ModeEnabled = (*env)->GetBooleanField(env, obj, rs485ModeField);
+	unsigned char rs485ActiveHigh = (*env)->GetBooleanField(env, obj, rs485ActiveHighField);
 	unsigned char isDtrEnabled = (*env)->GetBooleanField(env, obj, isDtrEnabledField);
 	unsigned char isRtsEnabled = (*env)->GetBooleanField(env, obj, isRtsEnabledField);
 	tcflag_t byteSize = (byteSizeInt == 5) ? CS5 : (byteSizeInt == 6) ? CS6 : (byteSizeInt == 7) ? CS7 : CS8;
@@ -374,9 +377,19 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	if (ioctl(serialPortFD, TIOCGRS485, &rs485Conf) == 0)
 	{
 		if (rs485ModeEnabled)
-			rs485Conf.flags |= SER_RS485_ENABLED; // Set these too? SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND
+			rs485Conf.flags |= SER_RS485_ENABLED;
 		else
-			rs485Conf.flags &= ~SER_RS485_ENABLED; // Clear these too? &= ~(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND);
+			rs485Conf.flags &= ~SER_RS485_ENABLED;
+		if (rs485ActiveHigh)
+		{
+			rs485Conf.flags |= SER_RS485_RTS_ON_SEND;
+			rs485Conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
+		}
+		else
+		{
+			rs485Conf.flags &= ~(SER_RS485_RTS_ON_SEND);
+			rs485Conf.flags |= SER_RS485_RTS_AFTER_SEND;
+		}
 		rs485Conf.delay_rts_before_send = rs485DelayBefore;
 		rs485Conf.delay_rts_after_send = rs485DelayAfter;
 		ioctl(serialPortFD, TIOCSRS485, &rs485Conf);

src/main/java/com/fazecast/jSerialComm/SerialPort.java

@@ -2,7 +2,7 @@
  * SerialPort.java
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Jan 03, 2020
+ *  Last Updated on:  Jan 22, 2020
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2020 Fazecast, Inc.
@@ -374,8 +374,8 @@ public final class SerialPort
 	private volatile SerialPortDataListener userDataListener = null;
 	private volatile SerialPortEventListener serialEventListener = null;
 	private volatile String comPort, friendlyName, portDescription;
-	private volatile boolean isOpened = false, disableConfig = false;
-	private volatile boolean rs485Mode = false, isRtsEnabled = true, isDtrEnabled = true;
+	private volatile boolean isOpened = false, disableConfig = false, rs485Mode = false;
+	private volatile boolean rs485ActiveHigh = true, isRtsEnabled = true, isDtrEnabled = true;
 
 	/**
 	 * Opens this serial port for reading and writing with an optional delay time and user-specified device buffer size.
@@ -855,17 +855,7 @@ public final class SerialPort
 	 */
 	public final void setComPortParameters(int newBaudRate, int newDataBits, int newStopBits, int newParity)
 	{
-		baudRate = newBaudRate;
-		dataBits = newDataBits;
-		stopBits = newStopBits;
-		parity = newParity;
-
-		if (isOpened)
-		{
-			if (safetySleepTimeMS > 0)
-				try { Thread.sleep(safetySleepTimeMS); } catch (Exception e) { Thread.currentThread().interrupt(); }
-			configPort(portHandle);
-		}
+		setComPortParameters(newBaudRate, newDataBits, newStopBits, newParity, rs485Mode);
 	}
 
 	/**
@@ -882,8 +872,8 @@ public final class SerialPort
 	 * The parity parameter specifies how error detection is carried out.  Again, the built-in constants should be used.
 	 * Acceptable values are {@link #NO_PARITY}, {@link #EVEN_PARITY}, {@link #ODD_PARITY}, {@link #MARK_PARITY}, and {@link #SPACE_PARITY}.
 	 * <p>
-	 * RS-485 mode can be used to enable transmit/receive mode signaling using the RTS pin. This mode should be set if you plan
-	 * to use this library with an RS-485 device. Note that this mode requires support from the underlying device driver, so it
+	 * RS-485 mode can be used to enable transmit/receive mode signaling using the RTS pin.  This mode should be set if you plan
+	 * to use this library with an RS-485 device.  Note that this mode requires support from the underlying device driver, so it
 	 * may not work with all RS-485 devices.
 	 *
 	 * @param newBaudRate The desired baud rate for this serial port.
@@ -1123,16 +1113,21 @@ public final class SerialPort
 	 * to use this library with an RS-485 device. Note that this mode requires support from the underlying device driver, so it
 	 * may not work with all RS-485 devices.
 	 * <p>
+	 * The RTS "active high" parameter specifies that the logical level of the RTS line will be set to 1 when transmitting and
+	 * 0 when receiving.
+	 * <p>
 	 * The delay parameters specify how long to wait before or after transmission of data before enabling or disabling
 	 * transmission mode via the RTS pin.
 	 *
 	 * @param useRS485Mode Whether to enable RS-485 mode.
+	 * @param rs485RtsActiveHigh Whether to set the RTS line to 1 when transmitting.
 	 * @param delayBeforeSendMicroseconds The time to wait after enabling transmit mode before sending the first data bit.
 	 * @param delayAfterSendMicroseconds The time to wait after sending the last data bit before disabling transmit mode.
 	 */
-	public final void setRs485ModeParameters(boolean useRS485Mode, int delayBeforeSendMicroseconds, int delayAfterSendMicroseconds)
+	public final void setRs485ModeParameters(boolean useRS485Mode, boolean rs485RtsActiveHigh, int delayBeforeSendMicroseconds, int delayAfterSendMicroseconds)
 	{
 		rs485Mode = useRS485Mode;
+		rs485ActiveHigh = rs485RtsActiveHigh;
 		rs485DelayBefore = delayBeforeSendMicroseconds;
 		rs485DelayAfter = delayAfterSendMicroseconds;