// Master

#include <SoftwareSerial.h>

#define RX    5   // MISO
#define TX    4   // SCK

#define button_pin 8
#define led_pin 7

SoftwareSerial Serial(RX, TX);

void setup() {
  // config button_pin als INPUT for a connected button (normally open; connects to GND)
  pinMode( button_pin, INPUT_PULLUP);
  // config led_pin as OUTPUT for a connected LED
  pinMode( led_pin, OUTPUT);
 // pinMode( 6, INPUT_PULLUP);
 // pinMode( 4, INPUT_PULLUP);
  
 Serial.begin(9600);
}

void loop() {
  // check, if the button was pressed
  if(digitalRead(button_pin) == 0){ 
  Serial.println("STARTING");
  Serial.write('O');
 if (Serial.available()) {
     char SlaveCommand = Serial.read();
     if(SlaveCommand == 'R') {
      digitalWrite(led_pin, HIGH);
     }
      
     }

  
  }
}