概述

本文介绍如何在 睿擎工业开发平台 中创建并运行 WDT 看门狗 示例工程。通过驱动 TL3576 平台内置看门狗定时器，演示了利用 RT-Thread 设备驱动框架进行 WDT 设备操作的完整流程。

WDT 看门狗

看门狗定时器（WatchDog Timer, WDT）是一种硬件计时电路，当系统因软件故障或外部干扰陷入死循环或崩溃时，能自动产生复位信号使系统恢复正常运行。

硬件连接

TL3576 平台的 WDT 看门狗外设集成在 SoC 内部，无需额外外部接线。WDT 定时器使用内部时钟源驱动，通过 APB 总线进行寄存器配置。

查手册获取 WDT 的超时参数

根据 TL3576 技术参考手册（TRM）可知：

• WDT 支持可编程超时时间，范围从数毫秒至数十秒
• 本示例配置超时时间为 6 秒

WDT 看门狗喂狗与超时复位

本示例展示如何通过 WDT 设备驱动接口初始化看门狗，创建独立的喂狗线程每 1 秒执行一次喂狗操作，在连续喂狗 10 次后停止喂狗，观察系统因超时而自动复位的完整过程。

构建与烧录

创建工程点击展开

1. 依次点击 “文件” -> “新建” -> "RT-Thread RuiChing App 项目"。

   

2. 在弹出新建向导中选择 开发版 、BSP: 、示例 、 调试器/下载器。选择好之后点击 “完成”。

   

3. 点击 “完成” 后，等待工程创建完成。

   

4. 创建完成。

   

构建工程点击展开

1. 单击工程使工程进入 Active-Debug 模式。

   

2. 点击工具栏上的构建按钮进行工程编译。

   

3. 构建成功后，会显示构建成功的信息。

   

固件下载点击展开

1. 固化驱动

   

2. 固化 APP

   

核心示例代码

wdt_example.c

static void wdt_feed_entry(void *parameter)// 看门狗喂狗线程
{
    rt_uint32_t count = 0;
    rt_uint32_t timeout = (rt_uint32_t)parameter;

    rt_kprintf("[WDT_TEST] Feed dog thread started. Setting Timeout: %d seconds.\n", timeout);

    while (count < 10)
    {
        rt_mutex_take(wdt_mutex, RT_WAITING_FOREVER);// 获取互斥量
        rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_KEEPALIVE, RT_NULL);
        rt_mutex_release(wdt_mutex);// 释放互斥量

        rt_uint32_t time_left = 0;
        rt_err_t ret = rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_GET_TIMELEFT, &time_left);
        if (ret == RT_EOK)
        {
            rt_kprintf("[WDT_TEST] Feeding... (%d/10), Time left: %d sec\n", count + 1, time_left);
        }
        else
        {
            rt_kprintf("[WDT_TEST] Feeding... (%d/10), get_timeleft unsupported\n", count + 1);
        }

        rt_thread_mdelay(1000);
        count++;
    }

    rt_uint32_t real_timeout = 0;
    rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_GET_TIMEOUT, &real_timeout);
    rt_kprintf("[WDT_TEST] Stop feeding dog. System will reset after %ds!\n", real_timeout);

    feed_thread = RT_NULL;
    while (1)
    {
        rt_thread_mdelay(500);
    }
}

int wdt_test(int argc, char **argv)// 看门狗测试入口函数
{
    rt_err_t ret = RT_EOK;
    rt_uint32_t timeout = WDT_TIMEOUT_SEC * 1000;
    rt_uint32_t wdt_type = 0;

    if (wdg_dev != RT_NULL || feed_thread != RT_NULL)
    {
        rt_kprintf("[WDT_TEST] WDT already running, please wait reset or reboot!\n");
        return -RT_EBUSY;
    }

    if (wdt_mutex == RT_NULL)
    {
        wdt_mutex = rt_mutex_create("wdt_mtx", RT_IPC_FLAG_FIFO);// 创建一个互斥量
        if (wdt_mutex == RT_NULL)
        {
            rt_kprintf("[WDT_TEST] Create mutex failed!\n");
            return -RT_ENOMEM;
        }
    }

    wdg_dev = rt_device_find(WDT_DEVICE_NAME);//寻找 wdt 设备
    if (!wdg_dev)
    {
        rt_kprintf("[WDT_TEST] Can't find watchdog device: %s\n", WDT_DEVICE_NAME);
        return -RT_ERROR;
    }

    ret = rt_device_open(wdg_dev, RT_DEVICE_FLAG_RDWR);//打开 wdt 设备
    if (ret != RT_EOK)
    {
        rt_kprintf("[WDT_TEST] Open watchdog failed, err: %d\n", ret);
        wdg_dev = RT_NULL;
        return ret;
    }

    ret = rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_SET_TIMEOUT, &timeout);//设置 wdt 超时时间
    if (ret != RT_EOK)
    {
        rt_kprintf("[WDT_TEST] Set timeout failed, err: %d\n", ret);
        rt_device_close(wdg_dev);
        wdg_dev = RT_NULL;
        return ret;
    }

    ret = rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_START, &wdt_type);//启动 wdt
    if (ret != RT_EOK)
    {
        rt_kprintf("[WDT_TEST] Start watchdog failed, err: %d\n", ret);
        rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_STOP, RT_NULL);//关闭 wdt
        rt_device_close(wdg_dev);
        wdg_dev = RT_NULL;
        return ret;
    }

    rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_KEEPALIVE, RT_NULL);//喂狗

    feed_thread = rt_thread_create("wdt_feed",
                                wdt_feed_entry,
                                (void *)WDT_TIMEOUT_SEC,
                                1024,
                                20,
                                10);// 动态初始化线程
    if (feed_thread != RT_NULL)
    {
        rt_thread_startup(feed_thread);
        rt_kprintf("[WDT_TEST] Feed thread created and started\n");
    }
    else
    {
        rt_kprintf("[WDT_TEST] Create feed thread failed!\n");
        rt_device_control(wdg_dev, RT_DEVICE_CTRL_WDT_STOP, RT_NULL);
        rt_device_close(wdg_dev);
        wdg_dev = RT_NULL;
        feed_thread = RT_NULL;
        return -RT_ENOMEM;
    }

    return RT_EOK;
}

运行示例

操作步骤

1. 将程序下载到开发板
2. 打开串口终端连接开发板
3. 在终端输入 wdt_test 命令运行
4. 观察终端日志：喂狗 10 次后停止喂狗，系统将在超时后自动复位

预期结果

验证 WDT 看门狗的基本通信及喂狗 / 超时复位功能正常。

RT-Thread 终端

msh />wdt_test
[DRV_WDT] SET_TIMEOUT: input 6000 ms
[DRV_WDT] match period 12, actual timeout 11 sec
[WDT_TEST] Feed thread created and started
msh />[WDT_TEST] Feed dog thread started. Setting Timeout: 6 seconds.
[WDT_TEST] Feeding... (1/10), Time left: 11 sec
[WDT_TEST] Feeding... (2/10), Time left: 11 sec
[WDT_TEST] Feeding... (3/10), Time left: 11 sec
[WDT_TEST] Feeding... (4/10), Time left: 11 sec
[WDT_TEST] Feeding... (5/10), Time left: 11 sec
[WDT_TEST] Feeding... (6/10), Time left: 11 sec
[WDT_TEST] Feeding... (7/10), Time left: 11 sec
[WDT_TEST] Feeding... (8/10), Time left: 11 sec
[WDT_TEST] Feeding... (9/10), Time left: 11 sec
[WDT_TEST] Feeding... (10/10), Time left: 11 sec
[WDT_TEST] Stop feeding dog. System will reset after 11s!

--- System reset ---