AVR sketch

gistfile1.txt

#include <avr/io.h>
#include <stdlib.h>
#include <avr/power.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>

int a;

void setup() {
  cli();

	a = 0;

	TCCR1A = 0;
	TCCR1B = (1 << WGM12) | (1 << CS10);
	TCNT1 = 0;
	OCR1A = 2022;
	TIMSK1 |= (1 << OCIE1A);

	DDRB = _BV(PINB4);
  sei();
}

ISR(TIMER1_COMPA_vect) {
	PORTB |= _BV(PINB4);
	int i = 5;
	while (i-- > 0)
		__asm__("nop\n\t");
	PORTB ^= _BV(PINB4);
}

int	main(void) {
	setup();

  for (;;) {
	}
	return 0;
}