为什么这个简单的STM32F756计时器代码不起作用？

Question

在apb1 = 96 MHz上采购到内部时钟，我想通过软件命令从零开始计数，并在达到自动填充寄存器值时生成计时器中断。我只有在使用HAL函数HAL_TIM_BASE_START_IT时，我才能使中断发射，该函数都激活更新中断并启动时钟。但是随后它立即发射而不是等待计数？

//********** timer initialization  ************************************
static void MX_TIM3_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig;
  TIM_MasterConfigTypeDef sMasterConfig;
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 1000;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 1000;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != 
   HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
}
//************  timer activation code in main program  ******************
    HAL_NVIC_DisableIRQ(TIM3_IRQn);
    TIM3->CR1 |= 0;
    TIM3->CNT=0;
    HAL_NVIC_ClearPendingIRQ(TIM3_IRQn);
    HAL_NVIC_EnableIRQ(TIM3_IRQn);
    TIM3->CR1 |= 1;
//****************   timer ISR  ***************************************
void TIM3_IRQHandler(void)
{
  doStuff();
  HAL_NVIC_ClearPendingIRQ(TIM3_IRQn);
  HAL_TIM_IRQHandler(&htim3);
}

Answer 1

如果您不希望启动开始后立即触发，请在启动计时器之前清除更新标志：

if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
  _Error_Handler(__FILE__, __LINE__);
}
__HAL_TIM_CLEAR_FLAG(&htim3, TIM_IT_UPDATE);
if(HAL_TIM_Base_Start_IT(&htim3) != HAL_OK)
{
  _Error_Handler(__FILE__, __LINE__);
}