Set TX pin to low when sending break

Author: sandeepmistry

src/RS485.cpp

@@ -19,8 +19,9 @@
 
 #include "RS485.h"
 
-RS485Class::RS485Class(HardwareSerial& hwSerial, int rePin, int dePin) :
+RS485Class::RS485Class(HardwareSerial& hwSerial, int txPin, int rePin, int dePin) :
   _serial(&hwSerial),
+  _txPin(txPin),
   _rePin(rePin),
   _dePin(dePin),
   _transmisionBegun(false)
@@ -82,6 +83,7 @@ void RS485Class::flush()
 size_t RS485Class::write(uint8_t b)
 {
   if (!_transmisionBegun) {
+    setWriteError();
     return 0;
   }
 
@@ -125,15 +127,19 @@ void RS485Class::noReceive()
 
 void RS485Class::sendBreak(unsigned int duration)
 {
+  _serial->flush();
   _serial->end();
+  pinMode(_txPin, OUTPUT);
+  digitalWrite(_txPin, LOW);
   delay(duration);
   _serial->begin(_baudrate, _config);
 }
 
-void RS485Class::setPins(int rePin, int dePin)
+void RS485Class::setPins(int txPin, int rePin, int dePin)
 {
+  _txPin = txPin;
   _rePin = rePin;
   _dePin = dePin;
 }
 
-RS485Class RS485(SERIAL_PORT_HARDWARE, RS845_DEFAULT_RE_PIN, RS845_DEFAULT_DE_PIN);
+RS485Class RS485(SERIAL_PORT_HARDWARE, RS485_DEFAULT_TX_PIN, RS845_DEFAULT_RE_PIN, RS845_DEFAULT_DE_PIN);

src/RS485.h

@@ -22,12 +22,13 @@
 
 #include <Arduino.h>
 
+#define RS485_DEFAULT_TX_PIN PIN_SERIAL1_TX
 #define RS845_DEFAULT_RE_PIN A5
 #define RS845_DEFAULT_DE_PIN A6
 
 class RS485Class : public HardwareSerial {
   public:
-    RS485Class(HardwareSerial& hwSerial, int rePin, int dePin);
+    RS485Class(HardwareSerial& hwSerial, int txPin, int rePin, int dePin);
 
     virtual void begin(unsigned long baudrate);
     virtual void begin(unsigned long baudrate, uint16_t config);
@@ -47,10 +48,11 @@ class RS485Class : public HardwareSerial {
 
     void sendBreak(unsigned int duration);
 
-    void setPins(int rePin, int dePin);
+    void setPins(int txPin, int rePin, int dePin);
 
   private:
     HardwareSerial* _serial;
+    int _txPin;
     int _rePin;
     int _dePin;