linux 应用层 gpio

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

#define GPIO_PIN "18"  // 假设使用GPIO18

void set_gpio_direction(const char *pin, const char *direction) {
    char path[64];
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%s/direction", pin);
    int fd = open(path, O_WRONLY);
    if (fd < 0) {
        perror("Failed to open gpio direction for writing");
        return;
    }
    write(fd, direction, strlen(direction));
    close(fd);
}

void set_gpio_value(const char *pin, int value) {
    char path[64];
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%s/value", pin);
    int fd = open(path, O_WRONLY);
    if (fd < 0) {
        perror("Failed to open gpio value for writing");
        return;
    }
    char val_str[2];
    snprintf(val_str, sizeof(val_str), "%d", value);
    write(fd, val_str, strlen(val_str));
    close(fd);
}

int main() {
    // 导出GPIO
    int export_fd = open("/sys/class/gpio/export", O_WRONLY);
    if (export_fd < 0) {
        perror("Failed to export gpio");
        return 1;
    }
    write(export_fd, GPIO_PIN, strlen(GPIO_PIN));
    close(export_fd);

    // 设置方向为输出
    set_gpio_direction(GPIO_PIN, "out");

    // 设置GPIO值为高电平
    set_gpio_value(GPIO_PIN, 1);

    // 延时
    sleep(1);

    // 设置GPIO值为低电平
    set_gpio_value(GPIO_PIN, 0);

    // 取消导出GPIO
    int unexport_fd = open("/sys/class/gpio/unexport", O_WRONLY);
    if (unexport_fd < 0) {
        perror("Failed to unexport gpio");
        return 1;
    }
    write(unexport_fd, GPIO_PIN, strlen(GPIO_PIN));
    close(unexport_fd);

    return 0;
}