text: #include <Arduino.h>
  
  #include <Arduino.h>
  #include <avr/interrupt.h>
  
  int main(void) {
    DDRD &= ~(1 << DDD5);
    PORTD |= (1 << PORTD5);
    TIMSK1 |= (1 << TOIE1);
    TCCR1B |= (1 << CS12) | (1 << CS11) | (1 << CS10);
    sei();
  
  while (1) {
  
  }
  }
  
  ISR(TIMER1_OVF_vect) {
  
  }