[经验]

【Milk-V Duo 开发板免费体验】2、C语言交叉编译控制LED

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2023-8-10 00:27:52

2151 C语言开发板试用

C语言交叉编译控制LED

参考教程：https://spotpear.cn/index/study/detail/id/1137.html

1、进入milkv，cat /proc/version

官方使用riscv64-unknown-linux-musl-gcc编译器，个人编译时也需要使用相同编译器。

2、为方便管理，在SDK下创建test文件夹，编写led.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h> //define O_WRONLY and O_RDONLY

// LED 引脚
#define SYSFS_GPIO_EXPORT "/sys/class/gpio/export"
#define SYSFS_GPIO_UNEXPORT "/sys/class/gpio/unexport"
#define SYSFS_GPIO_RST_PIN_VAL "440"
#define SYSFS_GPIO_RST_DIR "/sys/class/gpio/gpio440/direction"
#define SYSFS_GPIO_RST_DIR_VAL "OUT"
#define SYSFS_GPIO_RST_VAL "/sys/class/gpio/gpio440/value"
#define SYSFS_GPIO_RST_VAL_H "1"
#define SYSFS_GPIO_RST_VAL_L "0"

int main()
{
    int fd;
    int count = 30;

    // 打开端口/sys/class/gpio# echo 440 > export
    fd = open(SYSFS_GPIO_EXPORT, O_WRONLY);
    if (fd == -1)
    {
        printf("ERR: export open error.\n");
        return EXIT_FAILURE;
    }
    write(fd, SYSFS_GPIO_RST_PIN_VAL, sizeof(SYSFS_GPIO_RST_PIN_VAL));
    close(fd);

    // 设置端口方向/sys/class/gpio/gpio440# echo out > direction
    fd = open(SYSFS_GPIO_RST_DIR, O_WRONLY);
    if (fd == -1)
    {
        printf("ERR: direction open error.\n");
        return EXIT_FAILURE;
    }
    write(fd, SYSFS_GPIO_RST_DIR_VAL, sizeof(SYSFS_GPIO_RST_DIR_VAL));
    close(fd);

    // 输出复位信号: 拉高>100ns
    fd = open(SYSFS_GPIO_RST_VAL, O_RDWR);
    if (fd == -1)
    {
        printf("ERR: gpio open error.\n");
        return EXIT_FAILURE;
    }
    while (count)
    {
        count--;
        printf("milk:%d\r\n",count);
        write(fd, SYSFS_GPIO_RST_VAL_H, sizeof(SYSFS_GPIO_RST_VAL_H));
        usleep(1000000);
        write(fd, SYSFS_GPIO_RST_VAL_L, sizeof(SYSFS_GPIO_RST_VAL_L));
        usleep(1000000);
    }
    close(fd);

    // 打开端口/sys/class/gpio# echo 440 > unexport
    fd = open(SYSFS_GPIO_UNEXPORT, O_WRONLY);
    if (fd == -1)
    {
        printf("ERR: unexport open error.\n");
        return EXIT_FAILURE;
    }
    write(fd, SYSFS_GPIO_RST_PIN_VAL, sizeof(SYSFS_GPIO_RST_PIN_VAL));
    close(fd);

    return 0;
}