ATtiny13 timer - CTC interrupt

Pre overenie funkcie časovača je zapojenie obvodu jednoduché: ATtiny13 timer
#include <avr/io.h>
#include <avr/interrupt.h>

#define LED0 0

int main (void)
{
   DDRB |= (1 << LED0);

   TCCR0A |= (1<<WGM01); // Casovac - CTC Mode
   TIMSK0 |= (1<<OCIE0A); // Povol CTC interrupt
   TCCR0B |= ((1 << CS02) | (1 << CS00));  // CLOCK/1024
   OCR0A = 0xFD;

   while (1) {
     if (TIFR0 & (1 << OCF0A))
      {
          PORTB ^= (1 << LED0); // LED svieti/nesvieti           
          // zmaz CTC priznak 
          //(zapis logickej "1" vymaze priznak)
          TIFR0 = (1 << OCF0A); 
      }
   }
}