#include <stdio.h>
#include <stdlib.h>
#include <avr/interrupt.h>

uint8_t sleep_value;

ISR(TIMER0_OVF_vect)
{

if (sleep_value>0) {sleep_value--;};

}

void timer_start()
{

// (CL_1)
  TCCR0 = (1<<CS02)|(1<<CS00);  // Timer Clock = system clock / 1024
// (CL_2.0)
  TIFR  = 1<<TOV0;        // Clear TOV0 / Clear pending interrupts
// (CL_2.1)
  TIMSK = 1<<TOIE0;             // Enable Timer 0 Overflow Interrupt

}

void timer_sleep(uint8_t value)
{

sleep_value = value;

timer_start();

for(;;)
{
if (sleep_value == 0) break;
}

}

int main(void)
{

    sei();

    timer_sleep(2);
    cli();

for(;;);

}