long m = 0;
bool state = false;
bool interrupt = false;

void setup() {
  Serial.begin(115200);


  //LEDKY
  DDRD |= (1<<3);
  DDRD |= (1<<2);


  //TLAČITKO
  DDRD &= ~(1<<4);
  PORTD |= (1<<4); //PULLUP

  //prerušenie
  PCICR  |= 0b00000100;
  PCMSK2 |= 0b00010000;
}

void loop() {
  if(millis() - m > 500){
    m = millis();
    if(state == false){
      state = !state;
    }
    else if(state == true){
      state = !state;
    }
  }
  if(state == true){
    PORTD |= (1<<2);
  }
  else{
    PORTD &= ~(1<<2);
  }
  Serial.print("interrupt = ");
  Serial.println(interrupt);

  //prerušenie
  if(interrupt == true){
    Serial.println("Interrupt Active !");
    state = false;
    PORTD &= ~(1<<2);
    PORTD |= (1<<3);
    delay(500);
    interrupt = false;
    PORTD &= ~(1<<3);
  }
}

//prerušenie
ISR(PCINT2_vect){
  if((PIND & (1<<4))==0){
    interrupt = true;
  }
}