void setup() {
  DDRD |= (1 << PD7);
  cli();
    TCCR2A = 0;
    TCCR2B = 0;
    TCCR2B |= (1 << CS22) + (0 << CS21) + (0 << CS20);
    TIMSK2 |= (1 << TOIE1);
    TCNT2 = 6;
  sei();  
  Serial.begin(9600);
}

ISR (TIMER2_OVF_vect) {
  TCNT2 = 6;
  static int stevec = 0;
  stevec++;
  if (stevec >= 1000) {
    stevec = 0;
    PORTD ^= (1 << PD7);
  }
  Serial.println(stevec);
}

void loop() {
  
}