gpio.cpp

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>



int main()
{
    // Export the desired pin by writing to /sys/class/gpio/export

    int fd = open("/sys/class/gpio/export", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/gpio/export");
        exit(1);
    }

    if (write(fd, "418", 3) != 3) {
        perror("Error writing to /sys/class/gpio/export");
        exit(1);
    }

    close(fd);

    // Set the pin to be an output by writing "out" to /sys/class/gpio/gpio24/direction

    fd = open("/sys/class/gpio/gpio418/direction", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/gpio/gpio24/direction");
        exit(1);
    }

    if (write(fd, "out", 3) != 3) {
        perror("Error writing to /sys/class/gpio/gpio418/direction");
        exit(1);
    }

    close(fd);

    fd = open("/sys/class/gpio/gpio418/value", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/gpio/gpio418/value");
        exit(1);
    }

    // Toggle LED 500 ms on, 500ms off, 10 times (10 seconds)

    for (int i = 0; i < 10; i++) {
        if (write(fd, "1", 1) != 1) {
            perror("Error writing to /sys/class/gpio/gpio418/value");
            exit(1);
        }
        usleep(500000);

        if (write(fd, "0", 1) != 1) {
            perror("Error writing to /sys/class/gpio/gpio418/value");
            exit(1);
        }
        usleep(500000);
    }

    close(fd);

    // Unexport the pin by writing to /sys/class/gpio/unexport

    fd = open("/sys/class/gpio/unexport", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/gpio/unexport");
        exit(1);
    }

    if (write(fd, "418", 3) != 3) {
        perror("Error writing to /sys/class/gpio/unexport");
        exit(1);
    }

    close(fd);

    // And exit
    return 0;
}