void setup() {
  DDRD |= (1 << PD7);
  cli();
  TCCR2A = 0;
  TCCR2B = 0;
  TCCR2B |= (1 << CS22) + (1 << CS21) + (0 << CS20);
  TIMSK2 |= (1 << TOIE1);
  sei();
  Serial.begin(9600);
}

ISR(TIMER2_OVF_vect){
  static unsigned long stevec = 0;
  stevec++;
  PORTD ^= (1 << PD7);
  Serial.println(stevec);
}


void loop() {

}