arduino

const uint8_t wireIn = 14;
const uint8_t wireOut = 15;
int timer1_counter = 0;
int timer = 0;

void setup()
{
  pinMode(wireIn, INPUT);
  pinMode(wireOut, OUTPUT);
  noInterrupts();
  timer1_counter = 0xffff / 8;
  TCNT1 = timer1_counter;

  TCCR1A = 0;
  TCCR1B |= (1 << CS10);
  TIMSK1 |= (1 << TOIE1);
  interrupts();
}

ISR(TIMER1_OVF_vect) {
  TCNT1 = timer1_counter;
  timer++;
  
  digitalWrite(wireOut, timer % 2);
}

void loop()
{

  /* add main program code here */

}