RS485 And Arduino Mega

Projects Programming
1

Hi,

I have some troubles using a Mega with RS485 modules.

When using the same code with 2 Arduino Uno, no problem i'm receiving the "ok"
Now with 2 Megas, nothing happens
Thanks for your help!

#include "RS485_protocol.h"
#include <SoftwareSerial.h>

const byte ENABLE_PIN = 4;
const byte LED_PIN = 13;

SoftwareSerial rs485 (2, 3);  // receive pin, transmit pin

// callback routines
  
void fWrite (const byte what)
  {
  rs485.write (what);  
  }
  


void setup()
{
  rs485.begin (28800);
  pinMode (ENABLE_PIN, OUTPUT);  // driver output enable
  pinMode (LED_PIN, OUTPUT);  // built-in LED
}  // end of setup
  
byte old_level = 0;

void loop()
{

 
  

      
  // assemble message
  byte msg [] = { 
     15    // device 1
         // turn light on
  };

  // send to slave  
  digitalWrite (ENABLE_PIN, HIGH);  // enable sending
  sendMsg (fWrite, msg, sizeof msg);
  digitalWrite (ENABLE_PIN, LOW);  // disable sending

 

}  // end of loop

#include <SoftwareSerial.h>
#include "RS485_protocol.h"

SoftwareSerial rs485 (2, 3);  // receive pin, transmit pin
const byte ENABLE_PIN = 4;

void fWrite (const byte what)
  {
  rs485.write (what);  
  }
  
int fAvailable ()
  {
  return rs485.available ();  
  }

int fRead ()
  {
  return rs485.read ();  
  }
  
void setup()
{
  rs485.begin (28800);
  pinMode (ENABLE_PIN, OUTPUT);  // driver output enable
  Serial.begin(9600);
}

void loop()
{
  byte buf [10];
  
  byte received = recvMsg (fAvailable, fRead, buf, sizeof (buf));
  
  if (received)
    {
    if (buf [0] == 15)
     Serial.print("ok!!");
     }
      
  
    
   
    
  
   
}  // end of loop
2

Ok found, use pin 50 instead of 2, because supports interrupt.

3

Why not use one of the HardwareSerial ports on the Mega rather than using SoftwareSerial ?

...R