#include <avr/io.h>
#include "avr/interrupt.h"

    uint8_t    count;
/* Timer 0 Interrupt */
ISR(TIMER0_OVF_vect){

    count++;
    if(count==20){
        count=0;
        // Toogle LED
        PORTB=PORTB ^ 0x20;
    }
}

int main(void)
{
    TMR0_init();

    DDRB |= 1<<DDRB5;   // Direction of pin PB5 set as Output
    /* Replace with your application code */
    while (1) 
    {
    }
}

/********************************************************************************
                                TMR 0 Initialization
********************************************************************************/
void TMR0_init( void ){

    // enable timer overflow interrupt for both Timer0 and Timer1
    TIMSK0=(1 <<TOIE0) ;

    // set timer0 counter initial value to 0
    TCNT0=0x00;

    // start timer0 with /1024 prescaler
    TCCR0B = (1 <<CS02) | (1<<CS00);

    // enable interrupts
    sei(); 

}