物联网-移远M26模块OpenCPU开发第3讲（看门狗）

浅浅的花香味﹌ 2022-04-03 15:14 668阅读 0赞

之前在[物联网-移远M26模块OpenCPU开发第1讲][-_M26_OpenCPU_1]中提到过需要给外部看门狗芯片喂狗才能正常工作，阅读过的读者应该知道，我是通过周期性的控制M26的一个GPIO引脚电平变化来实现喂狗的。关于其硬件参考设计如下图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQ3NTQ4NDE_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQ3NTQ4NDE_size_16_color_FFFFFF_t_70 1][]

其实，移远M26 OpenCPU自带看门狗管理器，可以使用其内部看门狗管理器来进行喂狗，软件实现的原理如下图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQ3NTQ4NDE_size_16_color_FFFFFF_t_70 2][]

除了执行用户应用期间的喂狗，还可以在芯片启动时和远程升级软件时主动喂狗（没有验证过，后期会试一下远程升级软件功能），如下图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQ3NTQ4NDE_size_16_color_FFFFFF_t_70 3][]

当然在执行应用期间也需要用到定时器，调用Ql\_WTD\_Feed(wtd\_id)函数，具体理论知识我就不过多的阐述了，烦请读者自行阅读参考手册，里面有详细的操作方式和例程，详情参考：[ Quectel\_OpenCPU\_Watchdog\_Application\_Note\_V1.0][Quectel_OpenCPU_Watchdog_Application_Note_V1.0]

下面我上传一下我项目应用中用到的配置代码，如下：

// 定义定时器相关变量
    static u32 g_myTimerId_wtd = TIMER_ID_USER_START+2;             // 喂狗定时器ID   102 
    static u32 g_nInterval_wtd = 500;                               // 500ms中断
    
    void WTD_Program(void)
    {
    	s32 ret;
        s32 wtdid;
    	 	// Initialize external watchdog:
        // specify the GPIO pin (PINNAME_NETLIGHT) and the overflow time is 600ms.
        ret = Ql_WTD_Init(0, PINNAME_NETLIGHT, 600);
        if (0 == ret)
        {      		 
        	Ql_memset(pchData, 0x0, sizeof(pchData));					    		 
    		dataLen = Ql_sprintf(pchData, "\r\n<--OpenCPU: watchdog init OK!-->\r\n");	
    		Ql_UART_Write(UART_PORT1,(u8*)pchData,dataLen); 
        }
        // Create a logic watchdog, the interval is 3s
        wtdid = Ql_WTD_Start(3000);
    
        // Register & start a timer to feed the logic watchdog.
        // The watchdog id will be passed into callback function as parameter.
        ret = Ql_Timer_Register(g_myTimerId_wtd, Callback_OnTimer, &wtdid);
        if(ret < 0)
        {
    		Ql_memset(pchData, 0x0, sizeof(pchData));					    		 
    		dataLen = Ql_sprintf(pchData, "<--main task: register fail ret=%d-->\r\n",ret);	
    		Ql_UART_Write(UART_PORT1,(u8*)pchData,dataLen); 
            return;
        }
        // The real feeding interval is 2s
        ret = Ql_Timer_Start(g_myTimerId_wtd, 2000,TRUE);
        if(ret < 0)
        {
    		Ql_memset(pchData, 0x0, sizeof(pchData));					    		 
    		dataLen = Ql_sprintf(pchData, "<--main task: start timer fail ret=%d-->\r\n",ret);	
    		Ql_UART_Write(UART_PORT1,(u8*)pchData,dataLen);       
            return;
        }
    	Ql_memset(pchData, 0x0, sizeof(pchData));					    		 
    	dataLen = Ql_sprintf(pchData, "<--main task: start timer OK  ret=%d-->\r\n",ret);	
    	Ql_UART_Write(UART_PORT1,(u8*)pchData,dataLen); 
    }

请大家不要过多纠结函数中用到的变量，可以自行定义或者更改。当然了，上面只是初始化配置函数，还需在定时器回调函数里调用Ql\_WTD\_Feed()函数，代码如下：

// 定时器回调函数
    void Callback_OnTimer(u32 timerId, void* param)
    {
    	s32* wtdid = (s32*)param;
    	Ql_WTD_Feed(*wtdid);  		
       	Ql_memset(pchData, 0x0, sizeof(pchData));					    		 
    	dataLen = Ql_sprintf(pchData, "<-- time to feed logic watchdog (wtdId=%d) -->\r\n",*wtdid);	
    	Ql_UART_Write(UART_PORT1,(u8*)pchData,dataLen); 
     }

关于定时器相关知识请参考：[Quectel\_M26-OpenCPU\_User\_Guide\_V1.0][Quectel_M26-OpenCPU_User_Guide_V1.0]定时器相关章节。

到此，m26的看门狗功能也就讲完了，欢迎读者提出疑问，可以加群讨论：838839442 微信公众号：[物联网技术交流与学习][Link 1]

[-_M26_OpenCPU_1]: https://blog.csdn.net/u014754841/article/details/84196522
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQ3NTQ4NDE_size_16_color_FFFFFF_t_70 2]: /images/20220403/bf955ead5bea4575966715fe9e8efa95.png
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[Quectel_OpenCPU_Watchdog_Application_Note_V1.0]: https://download.csdn.net/download/u014754841/10870468
[Quectel_M26-OpenCPU_User_Guide_V1.0]: https://download.csdn.net/download/u014754841/10791196
[Link 1]: https://mp.weixin.qq.com/cgi-bin/settingpage?t=setting/index&action=index&token=1735041687&lang=zh_CN