STM32单片机：独立看门狗、窗口看门狗的配置 -

//时间计算(大概):Tout=((4*2^prer)*rlr)/40 (ms)
void IWDG_Init(u8 prer,u16 rlr)
{
      IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
      IWDG_SetPrescaler(prer);
      IWDG_SetReload(rlr);
      IWDG_ReloadCounter();
      IWDG_Enable();
}

以上描述可参考下图以更清晰的理解：窗口看门狗应用时还要注意算准最小与最大喂狗时间，以便正确地喂狗，如下：

//窗口看门狗中断服务设置程序

void WWDG_NVIC_Init()
{
   NVIC_InitTypeDef NVIC_InitStructure;
   NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
   NVIC_InitStructure.NVIC_IRQChannel = WWDG_IRQn;    //WWDG 中断
   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; //抢占2 子优先级3 组2
   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //抢占2,子优先级3,组2
   NVIC_Init(&NVIC_InitStructure);                      //NVIC 初始化
}

//初始化窗口看门狗
//tr  :T[6:0],计数器值
//wr :W[6:0],窗口值
//fprer:分频系数（WDGTB ）,仅最低2 位有效
//Fwwdg=PCLK1/(4096*2^fprer).
void WWDG_Init(u8 tr,u8 wr,u32 fprer)
{
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE); // WWDG 时钟使能
   WWDG_CNT=tr&WWDG_CNT;    //初始化WWDG_CNT.
   WWDG_SetPrescaler(fprer);       //设置IWDG 预分频值
   WWDG_SetWindowValue(wr);    //设置窗口值
   WWDG_Enable(WWDG_CNT);    //使能看门狗,设置counter
   WWDG_ClearFlag();             //清除提前唤醒中断标志位（注：若没有此句则会在初始化后先进入中断一次）
   WWDG_NVIC_Init();             //初始化窗口看门狗NVIC
   WWDG_EnableIT();             //开启窗口看门狗中断
}