Multiple Serial Ports Stream Switch

Question

I am trying to define multiple serial ports (multiple BMS management boards) and select via a global variable the port which one is active, this is the sketch I am trying to modify.

https://github.com/bres55/Smart-BMS-arduino-Reader/blob/master/smart_bms_reader_Mega_v11.ino

The function I want to write could be called "MySerialSwitch"

The smart_bms_reader_Mega_v11.ino has 19 calls to serial in a number of different functions. I want to be able to define the "active" MySerial in a variable that can be changed on the fly.

Something like this.

#include <SoftwareSerial.h>                   
SoftwareSerial MySoftSerial1(10, 11); // RX, TX
SoftwareSerial MySoftSerial2(12, 13); // RX, TX

#define MySerial1 MySoftSerial1
#define MySerial2 MySoftSerial2
#define MySerial3 Serial3

char MySerialPort[] = "MySerial1";


void setup()

{
MySoftSerial1.begin(9600);
MySoftSerial2.begin(9600);
Serial3.begin(9600);
}

This function would be modified

void call_get_cells_v()
{
  flush(); // flush first
  uint8_t data[7] = {221, 165, 4, 0, 255, 252, 119};
  MySerial.write(data, 7);
}

to read.

void call_get_cells_v()
{
  flush(); // flush first
  uint8_t data[7] = {221, 165, 4, 0, 255, 252, 119};
  MySerialSwitch.write(data, 7);
}

I have been researching this post

How to define a SoftwareSerial object inside a class?

And this post

Writing First Library - Serial Stream Object

It’s my first attempt at creating a library, I think this is kind of what I am trying to achieve, I've done the reading on stream, references and pointers. I'm not quite clear yet. I would really appreciate some assistance.

class MySerialSwitch {
    private:
        Stream *_dev;

    public:
        MySerialSwitch(Stream *dev) : _dev(dev) {}
        MySerialSwitch(Stream &dev) : _dev(&dev) {}
        (char MySerialPort);
};

    (int pos) {
    _dev->write(char MySerialPort);
}

Answer 1

I found this post, I don't think it will switch between hardware serial and software serial but it certainly works for just software.

#include <SoftwareSerial.h>                
SoftwareSerial MySoftSerial1(10, 11); // RX, TX 
SoftwareSerial MySoftSerial2(12, 13); // RX, TX 
SoftwareSerial *MySerial;


void setup()
    {

   Serial.begin(115200);
   MySoftSerial1.begin(9600);
   MySoftSerial2.begin(9600);
    }

    void loop()
    {
      MySerial = &MySoftSerial1; //Query the 1st BMS
      //or change port
      MySerial = &MySoftSerial2; //Query the 2nd BMS

      // I had to all instances of MySerial.write to MySerial->write  
    }

I'll keep reading to figure out what I've done but if anyone would like to explain, I'd be very appreciative.

This is the post I got the method from.

https://forum.arduino.cc/index.php?topic=605453.0

Thanks