STM32H7用三个定时器完成等精度测量的程序

下面是使用三个定时器实现高精度测量的 STM32H7 代码示例：

1. 首先，需要配置三个定时器，其中一个定时器充当计数器，另外两个定时器充当时间戳计时器。

// 定时器1为计数器
TIM_HandleTypeDef htim1;
// 定时器2和定时器3为时间戳计时器
TIM_HandleTypeDef htim2;
TIM_HandleTypeDef htim3;

void MX_TIM1_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_IC_InitTypeDef sConfigIC = {0};

  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 0;
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 65535;
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }

  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }

  if (HAL_TIM_IC_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }

  sConfigIC.ICPolarity = TIM_ICPOLARITY_RISING;
  sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
  sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
  sConfigIC.ICFilter = 0;
  if (HAL_TIM_IC_ConfigChannel(&htim1, &sConfigIC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
}

void MX_TIM2_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 9;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 65535;
  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();
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
}

void MX_TIM3_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 9;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 65535;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }

  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
}

2. 然后，需要在程序中编写相应的中断处理函数，以记录时间戳并计算时间差。

// 定时器2的中断处理函数
void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Instance == TIM2 && htim->Channel == HAL_TIM_ACTIVE_CHANNEL_1)
  {
    // 记录时间戳1
    timestamp1 = HAL_TIM_ReadCapturedValue(&htim2, TIM_CHANNEL_1);
  }
  else if (htim->Instance == TIM2 && htim->Channel == HAL_TIM_ACTIVE_CHANNEL_2)
  {
    // 记录时间戳2
    timestamp2 = HAL_TIM_ReadCapturedValue(&htim2, TIM_CHANNEL_2);

    // 计算时间差
    if (timestamp2 >= timestamp1)
    {
      time_diff = timestamp2 - timestamp1;
    }
    else
    {
      time_diff = (65535 - timestamp1) + timestamp2;
    }

    // 重置定时器2
    __HAL_TIM_SET_COUNTER(&htim2, 0);
  }
}

// 定时器3的中断处理函数
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Instance == TIM3)
  {
    // 计数器加1
    counter++;
  }
}

3. 最后，在主函数中启动定时器并进行测量。

int main(void)
{
  // ...

  // 初始化定时器
  MX_TIM1_Init();
  MX_TIM2_Init();
  MX_TIM3_Init();

  // 启动定时器1和定时器3
  HAL_TIM_Base_Start_IT(&htim1);
  HAL_TIM_Base_Start_IT(&htim3);

  while (1)
  {
    // 启动定时器2
    HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);
    HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_2);

    // 等待定时器2中断触发
    while (time_diff == 0)
    {
      // ...
    }

    // 停止定时器2
    HAL_TIM_IC_Stop_IT(&htim2, TIM_CHANNEL_1);
    HAL_TIM_IC_Stop_IT(&htim2, TIM_CHANNEL_2);

    // 输出计数器和时间差
    printf("Counter: %d, Time diff: %d us\r\n", counter, time_diff);
  }
}

这样，使用三个定时器就能实现高精度测量。其中，定时器1作为计数器，用于计算时间；定时器2和定时器3作为时间戳计时器，用于记录时间戳和计算时间差。需要注意的是，定时器2和定时器3的时钟频率需要一致，且需要使用同一个时钟源。