#include <avr/io.h>
/**
 * Internal clock of 1MHz
 */
main()
{
    DDRC |= _BV(PC5);
    TCCR0 = _BV(CS00) | _BV(CS02); // clk/1024 Mode
    while(1) {
        PORTC ^= _BV(PC5); // toggle PC5
        while(bit_is_clear(TIFR, TOV0));
        TIFR = _BV(TOV0);
    }
}