1.定时器配置初始化

将PA0引脚配置为定时器的外部输入引脚

void TIM_Init()
{
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
  GPIO_InitTypeDef GPIO_InitStruct;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStruct);
    
  TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0x00);
    
  TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
  TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInitStruct.TIM_Period = 10-1;
  TIM_TimeBaseInitStruct.TIM_Prescaler = 1-1;
  TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
    
  /*词条语句可避免此上电立即进入一次定时器中断的情况*/
  TIM_ClearFlag(TIM2, TIM_IT_Update);
    
  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
    
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  NVIC_InitTypeDef NVIC_InitStruct;
  NVIC_InitStruct.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
  NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 2;
  NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;
  NVIC_Init(&NVIC_InitStruct);
    
  TIM_Cmd(TIM2, ENABLE);
}

2.函数封装

将查询功能封装成一个函数，返回值为定时器2的外部输入计数值

uint16_t Timer_GetCounter()
{
  /*外部输入的计数可通过这个函数查询*/
  return TIM_GetCounter(TIM2);
}

3.中断回调函数

定时器每接收到一次外部输入都会进入中断，在这里我们可以写入一些我们想要执行的功能

void TIM2_IRQHandler(void)
{
  if(TIM_GetITStatus(TIM2, TIM_CounterMode_Up) == SET)
  {
    /*执行中断程序*/
    
        
    /*清楚中断标志位*/
    TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
  }
}

本次笔记基于B站UP主江协科技STM32教程总结而来

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