【已解决】CH32V303做看门狗的时候更改ReLoad无法影响超时时间

发布于 2024-12-06 15:59:26 浏览：312 订阅该版

在配置完包括预分频、重装值之后，看门狗重启时间仍然不变，从时间戳上看大概是27s
代码主要是从另一个项目上复制过来的，我本人对RT-Thread不是特别熟悉，发现问题之后看了一下往上的一些教程，从DEBUG里面跟了一下代码，发现问题还是解决不来，想向大家请假一下
初始化如下
```c
#ifdef WDT_ENABLE
    rt_device_t wdt;
    rt_uint32_t timeout;
    timeout = 1;
    wdt = rt_device_find("wdt");
    if (wdt != RT_NULL)
    {
        rt_device_control(wdt, RT_DEVICE_CTRL_WDT_SET_TIMEOUT, &timeout);
        rt_device_control(wdt, RT_DEVICE_CTRL_WDT_START, NULL);
    }
#endif
```
然后在系统启动的时候直接导入到一个死循环来测试看门狗，按理说在设置1s的超时时间后，应该会一直重启然后打印报文
```c
        switch (mode){
        case TEST_MODE:
            rt_kprintf("WDT START");
            while(1);
            break;
```
报文打印如下，时间间隔约为27s
```c
[15:47:20.253]收←◆
 \ | /
- RT -     Thread Operating System
 / | \     3.1.3 build Dec  6 2024
 2006 - 2019 Copyright by rt-thread team
 SysClk: 96000000Hz
 ChipID: 30310514
 Software version: V2.0.1
WDT START
[15:47:47.430]收←◆
 \ | /
- RT -     Thread Operating System
 / | \     3.1.3 build Dec  6 2024
 2006 - 2019 Copyright by rt-thread team
 SysClk: 96000000Hz
 ChipID: 30310514
 Software version: V2.0.1
WDT START
[15:48:14.603]收←◆
 \ | /
- RT -     Thread Operating System
 / | \     3.1.3 build Dec  6 2024
 2006 - 2019 Copyright by rt-thread team
 SysClk: 96000000Hz
 ChipID: 30310514
 Software version: V2.0.1
WDT START
```
我跟了一下drv_idwt.c里面的函数、操作，没有发现问题，看寄存器数值也都配进去了，但是超时时间任然没有变化，和上面的报文一样
![screenshot_7e00276eb4f888394f603b9d6795657.png](https://oss-club.rt-thread.org/uploads/20241206/472e67da778d0a198ca2b68293e5dc7b.png)

1 个回答

SixXxGod 2024-12-06

低头赶路，敬事如仪

SixXxGod 2024-12-09

低头赶路，敬事如仪

后续通过使用CH32V30X官方历程与drv_iwdt.c进行比较，发现在官方历程"IWDG"中的看门狗初始化顺序为

```c
void IWDG_Feed_Init(u16 prer, u16 rlr)
{
    IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
    IWDG_SetPrescaler(prer);
    IWDG_SetReload(rlr);
    IWDG_ReloadCounter();
    IWDG_Enable();
}
```
参考数据手册中的IWDG_RLDR寄存器定义得知，修改前需首先写入0x5555，在进行reload定义后，再写入0xAAAA进行计数器装载
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241209/ba46f2333a697fd42fe6ed1edacf9a46.png.webp)
在查看drv_iwdt.c中的控制函数得知控制顺序为

```c
IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
IWDG_SetPrescaler(wdt_dev->prescaler);
IWDG_SetReload(wdt_dev->reload);
IWDG_WriteAccessCmd(IWDG_WriteAccess_Disable);
IWDG_Enable();
```
总体流程无误，在reload值写方面不符合数据手册

```c
#define IWDG_WriteAccess_Enable     ((uint16_t)0x5555)
#define IWDG_WriteAccess_Disable    ((uint16_t)0x0000)
```
通过修改流程，在正确配置预分频与reload值后对寄存器写入0xAAAA后进行测试，系统重启时间与设定实现相符

```c
IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
IWDG_SetPrescaler(wdt_dev->prescaler);
IWDG_SetReload(wdt_dev->reload);
IWDG_ReloadCounter(); // 此处即为向寄存器写入0xAAAA，可改为IWDG_WriteAccessCmd(0xAAAA)
IWDG_Enable();
```

```c
[09:46:02.580]收←◆
 \ | /
- RT -     Thread Operating System
 / | \     3.1.3 build Dec  9 2024
 2006 - 2019 Copyright by rt-thread team
 SysClk: 96000000Hz
 ChipID: 30310514
 Software version: V2.0.1
reload time:468
reload time:468
arg time:2
GET TIMEOUT:0
reload time:468
arg time:2
GET TIMEOUT:0
WDT START
[09:46:05.731]收←◆
 \ | /
- RT -     Thread Operating System
 / | \     3.1.3 build Dec  9 2024
 2006 - 2019 Copyright by rt-thread team
 SysClk: 96000000Hz
 ChipID: 30310514
 Software version: V2.0.1
reload t
[09:46:05.778]收←◆ime:468
reload time:468
arg time:2
GET TIMEOUT:0
reload time:468
arg time:2
GET TIMEOUT:0
WDT START
```