sleep.c

#include <avr/io.h>

void sleep(const int milliseconds) {
	for (int j = 0; j < milliseconds; j++) {
	     for (int i = 0; i < (8000 / 18 - 28); i++);
	}
}

int main()
{
	DDRA = 0xFF;
	PORTA = 0b11101;
	
	while (1) {
		sleep(10000);
		PORTA = !PORTA;
	}
}