#include <SoftwareSerial.h>
#define RxD 2 //  WE ASSIGN PIN 2 FOR RX COMMUNICATION USING SOFTWARE SERIAL 
#define TxD 0 // //  WE ASSIGN PIN 0 FOR TX COMMUNICATION USING SOFTWARE SERIAL 

#define DEBUG_ENABLED  1
#define LED_A 4// THIS WE WANT TO CONTROL
#define LED_B 1// FOR TESTING POWER IN BOARD
 
SoftwareSerial mySerial(RxD,TxD);
void setup() {
 pinMode(RxD, INPUT);
 pinMode(TxD, OUTPUT);
 mySerial.begin(9600);
 pinMode(LED_A,OUTPUT);
 pinMode(LED_B,OUTPUT);
 digitalWrite(LED_B,HIGH); // ALWAYS HIGH FOR TESTING POWER IN BOARD2
}

void loop() {
if(mySerial.available()>0)
{
  int a = mySerial.read(); 
  
 if (a == 0)
 {
  digitalWrite(LED_A,HIGH);// WE CONTROL LED A ONLY FOR Board 1
 }
else 
{
   digitalWrite(LED_A,LOW);// WE CONTROL LED A ONLY for board 1
}
}}