#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(void)
{
	int i;
	int compteur = 0;
	int fd[3];
	char buffer[80];

	fd[0] = open("/sys/class/gpio/gpio26/value", O_WRONLY);
	fd[1] = open("/sys/class/gpio/gpio27/value", O_WRONLY);
	fd[2] = open("/sys/class/gpio/gpio28/value", O_WRONLY);
	if ((fd[0] < 0) || (fd[1] < 0) || (fd[2] < 0)) {
		perror("open");
		exit(EXIT_FAILURE);
	}
	while(1) {
		for (i = 0; i < 3; i ++) {
			sprintf(buffer, "%d", (compteur >> i) & 1);
			write(fd[i], buffer, 2);
		}
		compteur ++;
		compteur %= 8;
		usleep(100000);	
	}
}