#define set0(r,b) r&= ~(1<<b)
#define set1(r,b) r |= 1<<b
#define test(r,b) ( r&(1<<b) )

byte lastState;
int cislo = 0;

void setup() {

  Serial.begin(9600);

  //nastavenie zeleneho tlacitka
  set0(DDRD, 7); //input pcint23
  set1(PORTD, 7); //high

  //nastavenie cervenho tlacitka
  set0(DDRD, 6); //pcint22
  set1(PORTD, 6);

  //nastavenie modreho tlacitka
  set0(DDRD, 5); //pcint21
  set1(PORTD, 5);

  set1(PCICR, PCIE2); //zapnutie preruseni na PCIE2
  set1(SREG, 7); //globalne povolenie preruseni
  set1(PCMSK2, PCINT23); //zapnutie na konkretnom pine
  set1(PCMSK2, PCINT22);
  set1(PCMSK2, PCINT21);

  lastState = PIND; //nacitanie aktualneho stavu celeho registra

}



void loop() {
  // put your main code here, to run repeatedly:

}

ISR(PCINT2_vect) 
{
  if(test(PIND, 7) ==0   && test(lastState, 7) != test(PIND, 7)) //podmienka ci sa 
  //zmenil stav pinov. ak ano, znameno to ze na tomto pine prislo k prerusenie ak nie, do podmienky nevojde
  {
    cislo++;
    Serial.println(cislo);
  }

  if(test(PIND, 6) ==0   && test(lastState, 6) != test(PIND, 6))
  {
    cislo--;
    Serial.println(cislo);
  }

  if(test(PIND, 5) ==0   && test(lastState, 5) != test(PIND, 5))
  {
    cislo=0;
    Serial.println(cislo);
  }

  lastState = PIND; //zaktualizoovanie stavu pinov
}