STM32：TIM通道输入捕获

本文主要讲解如何使用TIMER通道的输入脉冲捕获功能。基于STM32F7的Timer2 Channel3来进行讲解。

配置时钟

Timer2的时钟频率，对应APB1 Timer。

 分频设置为96-1，这样设置定时器每次counter加1，对应的时间为1us（计时精度是1us）。Counter设置为最大即可，默认不使用定时器中断。

 每个通道对应一个GPIO。

 初始化流程

注意CubeMx生成代码不会开启捕捉，要调用HAL_TIM_IC_Start_IT进行捕捉。

/* TIM2 init function */
void MX_TIM2_Init(void)
{
 
  /* USER CODE BEGIN TIM2_Init 0 */
 
  /* USER CODE END TIM2_Init 0 */
 
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_IC_InitTypeDef sConfigIC = {0};
 
  /* USER CODE BEGIN TIM2_Init 1 */
 
  /* USER CODE END TIM2_Init 1 */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 96-1;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 0xFFFFFFFF;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_IC_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
  sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
  sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
  sConfigIC.ICFilter = 0;
  if (HAL_TIM_IC_ConfigChannel(&htim2, &sConfigIC, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_IC_ConfigChannel(&htim2, &sConfigIC, TIM_CHANNEL_4) != HAL_OK)
  {
    Error_Handler();
  }
 
  // Start Capture
  if(HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
 
  if(HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_4) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM2_Init 2 */
 
  /* USER CODE END TIM2_Init 2 */
 
}

捕获中断处理

 注意TIM输入捕获不会对捕获的脉冲进行计数，需要在中断处理函数里面进行累加处理。HAL_TIM_ACTIVE_CHANNEL_3对应当前输入捕获的Channel是TIM Channel 3。

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
    if(htim == &htim2)
    {
        if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_3) Curr_PGA_Counter++;
    }
}

对应时刻脉冲数

注意HAL_TIM_ReadCapturedValue获取的是以1us为单位的定时器的counter（对应时间），通过此函数可以获取捕捉到脉冲的瞬间对应的时刻。当没有捕获到新的脉冲的话，HAL_TIM_ReadCapturedValue的值返回最后一次脉冲捕获的时刻。如果定时器的counter period设置过小，会很快溢出，重新从0开始计数。建议counter period设置为最大。

uint32_t Get_PG_ChannelA_TimCounter(void)
{
    return HAL_TIM_ReadCapturedValue(&htim2, TIM_CHANNEL_3);
}
 
void PG_Test(void)
{
    //Pre_PGA_Counter = Curr_PGA_Counter;
    //Pre_PGB_Counter = Curr_PGB_Counter;
    uint32_t timer_us = Get_PG_ChannelA_TimCounter();
    double timer_s = (double)timer_us/1000000.0;
 
    Usart_Printf("PGA Counter: %d Timestamp: %fs\n", Curr_PGA_Counter, timer_s);
    //Usart_Printf("Curr_PGB_Counter: %d\n", Curr_PGB_Counter);
}

结果测试：