问题

在使用按键配置外部中断时，使用HAL_Delay函数进行延时消抖，当进入中断时程序卡死无反应，去除HAL_Delay后恢复正常

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void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
	
  if(GPIO_Pin==KEY1_Pin)
  {
    HAL_Delay(20);/* 延时一小段时间，消除抖动 */
		if(HAL_GPIO_ReadPin(KEY1_GPIO_Port,KEY1_Pin)==1)
    {
			HAL_Delay(20);
			if(HAL_GPIO_ReadPin(KEY1_GPIO_Port,KEY1_Pin)==1)
			{
				printf("KEY=1\n");
				
			}
     	
    }
    __HAL_GPIO_EXTI_CLEAR_IT(GPIO_Pin);
  }
}

原因

查看HAL_Delay相关程序发现，HAL_Delay是通过滴答定时器的中断进行延迟。

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/**
  * @brief This function provides minimum delay (in milliseconds) based
  *        on variable incremented.
  * @note In the default implementation , SysTick timer is the source of time base.
  *       It is used to generate interrupts at regular time intervals where uwTick
  *       is incremented.
  * @note This function is declared as __weak to be overwritten in case of other
  *       implementations in user file.
  * @param Delay specifies the delay time length, in milliseconds.
  * @retval None
  */
__weak void HAL_Delay(uint32_t Delay)
{
  uint32_t tickstart = HAL_GetTick();
  uint32_t wait = Delay;

  /* Add a freq to guarantee minimum wait */
  if (wait < HAL_MAX_DELAY)
  {
    wait += (uint32_t)(uwTickFreq);
  }

  while ((HAL_GetTick() - tickstart) < wait)
  {
  }
}

进而查找滴答定时器相关初始化发现，在程序初始化时默认把滴答定时器的中断优先级设为最低。

默认初始化

解决方法

我们可以在main的初始化后里加上如下指令把滴答定时器优先级调为最高，问题解决。

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HAL_NVIC_SetPriority(SysTick_IRQn,0,0U);