Mikrokontrolery 2

#include<avr/io.h>


    int main(void){
    DDRA = 0xff;
    for(;;){
        PORTA = _BV(3) | _BV(4);
        for(int i = 3;i >=0;i--){
            PORTA |= _BV(i) | _BV(7-i);
            for(unsigned long i=0; i<=16000;i++){
                __asm__ ( "nop;");
            }
        };
        for(int i=0;i<3;i++){
            PORTA &= ~(_BV(i) | _BV(7-i));
            for(unsigned long i=0; i<=16000;i++){
                __asm__ ( "nop;");
            }

        };

    }
return 0;
}