//to display even numbers from 0-9

#include <stdint.h>

#define DDRA  (*(volatile uint8_t*)0x21)
#define PORTA (*(volatile uint8_t*)0x22)

uint8_t seg[10] = {
    0x3F,
    0x06,
    0x5B,
    0x4F,
    0x66,
    0x6D,
    0x7D,
    0x07,
    0x7F,
    0x6F
};

void delay1sec(void){
    TCNT1 = 0;
    TCCR1A = 0x00;
    TCCR1B = 0x05;
    while (TCNT1 < 15625);
    TCCR1B = 0x00;
}

int main(void){
    DDRA = 0x7F;

    while (1){
        for (uint8_t i = 0; i <= 8; i += 2){
            PORTA = seg[i];
            delay1sec();
        }
    }
}