#include <avr\io.h>
#include <avr\interrupt.h>


#define outp(a, b) b = a

/*contains total ticks */
unsigned long ticks = 0;

/* interrupt handler */
ISR(SIG_OVERFLOW0) {
	ticks++;
}

int main (void)
{
	/*enable timer overflow interrupt*/

	outp((1<<TOV0), TIMSK);

	/*set timer counter initial value*/

	TCNT0=0x00;

	/*start timer without presscaler*/

	outp((1<<CS00), TCCR0);

	/* enable interrupts */

	ticks = 0;

	sei(); 

	while(1);
}