void setup() {
  DDRD |= (1<<PD7);
  cli();
  TCCR2A = 0;
  TCCR2B = 0;
  TCCR2B |= (1<<CS22) + (1<<CS21) + (1<<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() {
  // put your main code here, to run repeatedly:

}