USBtoRS485Test.cpp

#include "HardwareSerial.h"

HardwareSerial SerialTwo(2);

const char PIN_RS485 = 14; 
const unsigned short lineDriveOff = 10; 
const unsigned short lineDriveOn = 3; 

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(115200);
  SerialTwo.begin(115200);

   pinMode(PIN_RS485, OUTPUT);
   SetRX(); 
}


void SetTX() {
  digitalWrite(PIN_RS485, HIGH);
  delay(lineDriveOn);
}
void SetRX() {
  delay(lineDriveOff);
  digitalWrite(PIN_RS485, LOW);
  delay(lineDriveOn);
}

void loop() {

  static unsigned int serialOneRX = 0 ;
  static unsigned int serialOneTX = 0 ;
  static unsigned int serialTwoRX = 0 ;
  static unsigned int serialTwoTX = 0 ;

  // Send anything from RS485 port to USB serial 
  while (SerialTwo.available()) {
    char rc = SerialTwo.read();
    Serial.print(rc);
    serialTwoRX++;
    serialOneTX++;   }

  // Send anything from USB port to RS485 serial 
  while (Serial.available()) {
    char rc = Serial.read();
    
    SetTX(); 
    SerialTwo.print(rc);

    serialOneRX++;
    serialTwoTX++;     
  }
  SetRX(); 


  static unsigned long lastUpdate = 0 ; 
  if( lastUpdate < millis() ) {
    lastUpdate =  millis() + 5000 ; 

    SetTX(); 
    Serial.print( "\r\n" + String(millis()) + " FYI: Serial One TX: " + String(serialOneTX) + ", RX: "+ String(serialOneRX) + " Serial Two TX: " + String(serialTwoTX) + ", RX: "+ String(serialTwoRX) );
    SerialTwo.print( "\r\n" + String(millis()) + " FYI: Serial One TX: " + String(serialOneTX) + ", RX: "+ String(serialOneRX) + " Serial Two TX: " + String(serialTwoTX) + ", RX: "+ String(serialTwoRX) );
    SetRX(); 
  }
}