STM32H7定时器输入捕获功能实现

只看该作者 · 2018-8-10 15:54

说明：

通过输入捕获功能可以测量脉宽和信号周期，占空比等信息。

测试的官方例子：TIM_InputCapture

使用的定时器1的CC2。

最新分辨率是200 MHz / 65535 ≈ 3051Hz

代码如下：
int main(void)
{
  /* Enable the CPU Cache */
  CPU_CACHE_Enable();

  /* STM32H7xx HAL library initialization:
   - Systick timer is configured by default as source of time base, but user
      can eventually implement his proper time base source (a general purpose
      timer for example or other time source), keeping in mind that Time base
      duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
      handled in milliseconds basis.
   - Set NVIC Group Priority to 4
   - Low Level Initialization
   */
  HAL_Init();

  /* Configure the system clock to 400 MHz */
  SystemClock_Config();

  /*##-1- Configure the TIM peripheral #######################################*/
  /* TIM1 configuration: Input Capture mode ---------------------
   The external signal is connected to TIM1 CH2 pin (PE.11)
   The Rising edge is used as active edge,
   The TIM1 CCR2 is used to compute the frequency value
  ------------------------------------------------------------ */

  /* Set TIMx instance */
  TimHandle.Instance = TIMx;

  /* Initialize TIMx peripheral as follows:
   + Period = 0xFFFF
   + Prescaler = 0
   + ClockDivision = 0
   + Counter direction = Up
  */
  TimHandle.Init.Period          = 0xFFFF;
  TimHandle.Init.Prescaler       = 0;
  TimHandle.Init.ClockDivision    = 0;
  TimHandle.Init.CounterMode    = TIM_COUNTERMODE_UP;
  TimHandle.Init.RepetitionCounter = 0;
  if(HAL_TIM_IC_Init(&TimHandle) != HAL_OK)
  {
/* Initialization Error */
Error_Handler();
  }

  /*##-2- Configure the Input Capture channel ################################*/
  /* Configure the Input Capture of channel 2 */
  sICConfig.ICPolarity  = TIM_ICPOLARITY_RISING;
  sICConfig.ICSelection = TIM_ICSELECTION_DIRECTTI;
  sICConfig.ICPrescaler = TIM_ICPSC_DIV1;
  sICConfig.ICFilter = 0;
  if(HAL_TIM_IC_ConfigChannel(&TimHandle, &sICConfig, TIM_CHANNEL_2) != HAL_OK)
  {
/* Configuration Error */
Error_Handler();
  }

  /*##-3- Start the Input Capture in interrupt mode ##########################*/
  if(HAL_TIM_IC_Start_IT(&TimHandle, TIM_CHANNEL_2) != HAL_OK)
  {
/* Starting Error */
Error_Handler();
  }

  while (1)
  {
  }
}

/**
  * @brief  Conversion complete callback in non blocking mode
  * @param  htim : hadc handle
  * @retval None
  */
void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_2)
  {
if(uhCaptureIndex == 0)
{
   /* Get the 1st Input Capture value */
   uwIC2Value1 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_2);
   uhCaptureIndex = 1;
}
else if(uhCaptureIndex == 1)
{
   /* Get the 2nd Input Capture value */
   uwIC2Value2 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_2);

   /* Capture computation */
   if (uwIC2Value2 > uwIC2Value1)
   {
      uwDiffCapture = (uwIC2Value2 - uwIC2Value1);
   }
   else if (uwIC2Value2 < uwIC2Value1)
   {
      /* 0xFFFF is max TIM1_CCRx value */
      uwDiffCapture = ((0xFFFF - uwIC2Value1) + uwIC2Value2) + 1;
   }
   else
   {
      /* If capture values are equal, we have reached the limit of frequency
         measures */
      Error_Handler();
   }
   /* Frequency computation: for this example TIMx (TIM1) is clocked by
      2*APB2Clk as APB2CLKDivider are set to RCC_APB2_DIV2 */
   uwFrequency = 2*HAL_RCC_GetPCLK2Freq() / uwDiffCapture;
   uhCaptureIndex = 0;
}
  }
}

STM32H7定时器输入捕获功能实现

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