请教独立看门狗定时器校准

只看该作者 · 2018-12-19 15:54

void TIM5_IRQHandler(void)
{
  if (TIM_GetITStatus(TIM5, TIM_IT_CC4) != RESET)
  {
if(CaptureNumber == 0)
{
   /* Get the Input Capture value */
   IC1ReadValue1 = TIM_GetCapture4(TIM5);
}
else if(CaptureNumber == 1)
{
   /* Get the Input Capture value */
   IC1ReadValue2 = TIM_GetCapture4(TIM5);

   /* Capture computation */
   if (IC1ReadValue2 > IC1ReadValue1)
   {
      Capture = (IC1ReadValue2 - IC1ReadValue1);
   }
   else
   {
      Capture = ((0xFFFF - IC1ReadValue1) + IC1ReadValue2);
   }
   /* Frequency computation */
   LsiFreq = (uint32_t) SystemCoreClock / Capture;
   LsiFreq *= 8;
}

CaptureNumber++;

/* Clear TIM5 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(TIM5, TIM_IT_CC4);
  }
}
ST官方的例程，用于检测内部LSI时钟频率，为什么计算出来的频率要乘以8
LsiFreq *= 8;