tinkercad I2C communication between controllers

//Master

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd1(0x21,16,2);

byte board_address = 1;

byte Right[8] = {

  0b00000,

0b00100,

0b00110,

  0b11111,

  0b00110,

  0b00100,

  0b00000,

  0b00000,

};

byte x;

void setup()

{

  lcd1.init();

  lcd1.clear(); 

  lcd1.backlight(); 

  lcd1.createChar(0, Right);

  

  Wire.begin(1); 

  

}

void loop()

{ 

  //transmit to slave 2 and 3, then wait for slave response

  for(int i=2; i<4; i++){

    x=random(0, 255);

    

  Wire.beginTransmission(i); // transmit to device #2

  Wire.write(x);              // sends x 

  Wire.endTransmission();    // stop transmitting

 

  lcd1.setCursor(0,0);

  lcd1.clear(); 

  lcd1.print("M ");

  lcd1.write(0);

    lcd1.write(0);

  lcd1.print(" S");

  lcd1.print(i);

  lcd1.print("  ");

  lcd1.print(x);

 

  Wire.requestFrom(i, 2); //request 2 bytes from device 2 

  lcd1.setCursor(0,1);

 

  while(Wire.available()) {

    byte data = Wire.read(); 

    

  lcd1.print("S");

    lcd1.print(data); //1st byte is slave address

  lcd1.print(" ");

      lcd1.write(0);

      lcd1.write(0);

  lcd1.print(" M");

  lcd1.print("  ");

    

    data = Wire.read(); 

  lcd1.print(data); //2nd byte is echo data

  }

 

  delay(500);

  }

}

---------------------------

//Slave

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

byte board_address = 2;

byte data;

void setup()

{

  Wire.begin(board_address);               

  Wire.onReceive(receiveEvent);

  Wire.onRequest(requestEvent);

}

void loop()

{

  

}

void receiveEvent(int n) {

  

  

  while(Wire.available()) {

    data = Wire.read(); 

  }

}

void requestEvent() {

  Wire.write(board_address);

  Wire.write(data);

}

reference:

https://docs.arduino.cc/learn/communication/wire

I2C lcd

https://chuanshuoge3.blogspot.com/2022/06/tinkercad-i2c-lcds.html