#include <avr/io.h>
#include <SoftwareSerial.h>
#define BUTTON PIN_PA6
#define LED   PIN_PA7

SoftwareSerial mySerial(2, 3); // RX, TX (ATTiny DIGITAL/ANALOG pin number)

const char node = '2'; // network address
int incomingByte;

void setup() {
  mySerial.begin(9600);
  pinMode(BUTTON, INPUT);
  pinMode(LED, OUTPUT);
  pinMode(3, INPUT);
}

void loop() {
  if(!(digitalRead(BUTTON))) {
    digitalWrite(LED, HIGH);
    pinMode(3, OUTPUT); // open line to write
    mySerial.print("node ");
    mySerial.println(node);
    pinMode(3, INPUT);
  }

  if (mySerial.available()) {
    incomingByte = mySerial.read();
    if (incomingByte == node) {
      digitalWrite(LED, LOW);
    }
  }

}