HAL库USART中断接收的相关问题

抠脚学代码2025-02-14 13:14

文章目录

一、使用中断的步骤

1、配置GPIO

2、配置USART1

3、设置UART1中断优先级（不开启手动中断，中断由HAL库给好的函数开启）

4、设置USART1中断服务函数（调用HAL给好的中断服务函数）

5、设置回调函数（HAL定义了一个弱函数，需要用户自己重定义）

6、开启USART1接收中断

二、相关函数分析

1、HAL_UART_IRQHandler

在中断服务函数USART1_IRQHandler中调用，进行USART中断的处理。

c 复制代码 
void USART1_IRQHandler(void)
{
	HAL_UART_IRQHandler(&huart1);
}

查看函数源码

c 复制代码 
void HAL_UART_IRQHandler(UART_HandleTypeDef *huart)
{
  uint32_t isrflags   = READ_REG(huart->Instance->SR); //#define READ_REG(REG)         ((REG))
  uint32_t cr1its     = READ_REG(huart->Instance->CR1);
  uint32_t cr3its     = READ_REG(huart->Instance->CR3);
  uint32_t errorflags = 0x00U;
  uint32_t dmarequest = 0x00U;

  /* If no error occurs */
  errorflags = (isrflags & (uint32_t)(USART_SR_PE | USART_SR_FE | USART_SR_ORE | USART_SR_NE));
  //USART_SR_PE 32位，PE位为1，其余为0，是一个掩码  #define USART_SR_PE   USART_SR_PE_Msk  
  //  isrflags 时SR的值，与这几位的掩码与，若这些位无置位则结果位0.表示错误位都没有置为，无错误发生
  if (errorflags == RESET)// == 0 无错误
  {
    /* UART in mode Receiver -------------------------------------------------*/
    if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))
    {//接收数据寄存器非空 且 接收中断使能
      UART_Receive_IT(huart);//中断接收函数
      return;
    }
  }
//错误发生时
  /* If some errors occur */
  if ((errorflags != RESET) && (((cr3its & USART_CR3_EIE) != RESET)
                                || ((cr1its & (USART_CR1_RXNEIE | USART_CR1_PEIE)) != RESET)))
  {
    /* UART parity error interrupt occurred ----------------------------------*/
    if (((isrflags & USART_SR_PE) != RESET) && ((cr1its & USART_CR1_PEIE) != RESET))
    {
      huart->ErrorCode |= HAL_UART_ERROR_PE;
    }

    /* UART noise error interrupt occurred -----------------------------------*/
    if (((isrflags & USART_SR_NE) != RESET) && ((cr3its & USART_CR3_EIE) != RESET))
    {
      huart->ErrorCode |= HAL_UART_ERROR_NE;
    }

    /* UART frame error interrupt occurred -----------------------------------*/
    if (((isrflags & USART_SR_FE) != RESET) && ((cr3its & USART_CR3_EIE) != RESET))
    {
      huart->ErrorCode |= HAL_UART_ERROR_FE;
    }

    /* UART Over-Run interrupt occurred --------------------------------------*/
    if (((isrflags & USART_SR_ORE) != RESET) && (((cr1its & USART_CR1_RXNEIE) != RESET)
                                                 || ((cr3its & USART_CR3_EIE) != RESET)))
    {
      huart->ErrorCode |= HAL_UART_ERROR_ORE;
    }

    /* Call UART Error Call back function if need be --------------------------*/
    if (huart->ErrorCode != HAL_UART_ERROR_NONE)
    {
      /* UART in mode Receiver -----------------------------------------------*/
      if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))
      {
        UART_Receive_IT(huart);
      }

      /* If Overrun error occurs, or if any error occurs in DMA mode reception,
         consider error as blocking */
      dmarequest = HAL_IS_BIT_SET(huart->Instance->CR3, USART_CR3_DMAR);
      if (((huart->ErrorCode & HAL_UART_ERROR_ORE) != RESET) || dmarequest)
      {
        /* Blocking error : transfer is aborted
           Set the UART state ready to be able to start again the process,
           Disable Rx Interrupts, and disable Rx DMA request, if ongoing */
        UART_EndRxTransfer(huart);

        /* Disable the UART DMA Rx request if enabled */
        if (HAL_IS_BIT_SET(huart->Instance->CR3, USART_CR3_DMAR))
        {
          ATOMIC_CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAR);

          /* Abort the UART DMA Rx channel */
          if (huart->hdmarx != NULL)
          {
            /* Set the UART DMA Abort callback :
               will lead to call HAL_UART_ErrorCallback() at end of DMA abort procedure */
            huart->hdmarx->XferAbortCallback = UART_DMAAbortOnError;
            if (HAL_DMA_Abort_IT(huart->hdmarx) != HAL_OK)
            {
              /* Call Directly XferAbortCallback function in case of error */
              huart->hdmarx->XferAbortCallback(huart->hdmarx);
            }
          }
          else
          {
            /* Call user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
            /*Call registered error callback*/
            huart->ErrorCallback(huart);
#else
            /*Call legacy weak error callback*/
            HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
          }
        }
        else
        {
          /* Call user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
          /*Call registered error callback*/
          huart->ErrorCallback(huart);
#else
          /*Call legacy weak error callback*/
          HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
        }
      }
      else
      {
        /* Non Blocking error : transfer could go on.
           Error is notified to user through user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
        /*Call registered error callback*/
        huart->ErrorCallback(huart);
#else
        /*Call legacy weak error callback*/
        HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */

        huart->ErrorCode = HAL_UART_ERROR_NONE;
      }
    }
    return;
  } /* End if some error occurs */

  /* Check current reception Mode :
     If Reception till IDLE event has been selected : */
  if ((huart->ReceptionType == HAL_UART_RECEPTION_TOIDLE)
      && ((isrflags & USART_SR_IDLE) != 0U)
      && ((cr1its & USART_SR_IDLE) != 0U))
  {
    __HAL_UART_CLEAR_IDLEFLAG(huart);

    /* Check if DMA mode is enabled in UART */
    if (HAL_IS_BIT_SET(huart->Instance->CR3, USART_CR3_DMAR))
    {
      /* DMA mode enabled */
      /* Check received length : If all expected data are received, do nothing,
         (DMA cplt callback will be called).
         Otherwise, if at least one data has already been received, IDLE event is to be notified to user */
      uint16_t nb_remaining_rx_data = (uint16_t) __HAL_DMA_GET_COUNTER(huart->hdmarx);
      if ((nb_remaining_rx_data > 0U)
          && (nb_remaining_rx_data < huart->RxXferSize))
      {
        /* Reception is not complete */
        huart->RxXferCount = nb_remaining_rx_data;

        /* In Normal mode, end DMA xfer and HAL UART Rx process*/
        if (huart->hdmarx->Init.Mode != DMA_CIRCULAR)
        {
          /* Disable PE and ERR (Frame error, noise error, overrun error) interrupts */
          ATOMIC_CLEAR_BIT(huart->Instance->CR1, USART_CR1_PEIE);
          ATOMIC_CLEAR_BIT(huart->Instance->CR3, USART_CR3_EIE);

          /* Disable the DMA transfer for the receiver request by resetting the DMAR bit
             in the UART CR3 register */
          ATOMIC_CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAR);

          /* At end of Rx process, restore huart->RxState to Ready */
          huart->RxState = HAL_UART_STATE_READY;
          huart->ReceptionType = HAL_UART_RECEPTION_STANDARD;

          ATOMIC_CLEAR_BIT(huart->Instance->CR1, USART_CR1_IDLEIE);

          /* Last bytes received, so no need as the abort is immediate */
          (void)HAL_DMA_Abort(huart->hdmarx);
        }

        /* Initialize type of RxEvent that correspond to RxEvent callback execution;
        In this case, Rx Event type is Idle Event */
        huart->RxEventType = HAL_UART_RXEVENT_IDLE;

#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
        /*Call registered Rx Event callback*/
        huart->RxEventCallback(huart, (huart->RxXferSize - huart->RxXferCount));
#else
        /*Call legacy weak Rx Event callback*/
        HAL_UARTEx_RxEventCallback(huart, (huart->RxXferSize - huart->RxXferCount));
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
      }
      return;
    }
    else
    {
      /* DMA mode not enabled */
      /* Check received length : If all expected data are received, do nothing.
         Otherwise, if at least one data has already been received, IDLE event is to be notified to user */
      uint16_t nb_rx_data = huart->RxXferSize - huart->RxXferCount;
      if ((huart->RxXferCount > 0U)
          && (nb_rx_data > 0U))
      {
        /* Disable the UART Parity Error Interrupt and RXNE interrupts */
        ATOMIC_CLEAR_BIT(huart->Instance->CR1, (USART_CR1_RXNEIE | USART_CR1_PEIE));

        /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */
        ATOMIC_CLEAR_BIT(huart->Instance->CR3, USART_CR3_EIE);

        /* Rx process is completed, restore huart->RxState to Ready */
        huart->RxState = HAL_UART_STATE_READY;
        huart->ReceptionType = HAL_UART_RECEPTION_STANDARD;

        ATOMIC_CLEAR_BIT(huart->Instance->CR1, USART_CR1_IDLEIE);

        /* Initialize type of RxEvent that correspond to RxEvent callback execution;
           In this case, Rx Event type is Idle Event */
        huart->RxEventType = HAL_UART_RXEVENT_IDLE;

#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
        /*Call registered Rx complete callback*/
        huart->RxEventCallback(huart, nb_rx_data);
#else
        /*Call legacy weak Rx Event callback*/
        HAL_UARTEx_RxEventCallback(huart, nb_rx_data);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
      }
      return;
    }
  }

  /* UART in mode Transmitter ------------------------------------------------*/
  if (((isrflags & USART_SR_TXE) != RESET) && ((cr1its & USART_CR1_TXEIE) != RESET))
  {
    UART_Transmit_IT(huart);
    return;
  }

  /* UART in mode Transmitter end --------------------------------------------*/
  if (((isrflags & USART_SR_TC) != RESET) && ((cr1its & USART_CR1_TCIE) != RESET))
  {
    UART_EndTransmit_IT(huart);
    return;
  }
}

2、UART_Receive_IT

中断接收函数，被HAL_UART_IRQHandler 调用

c 复制代码 
static HAL_StatusTypeDef UART_Receive_IT(UART_HandleTypeDef *huart)
{
  uint8_t  *pdata8bits;
  uint16_t *pdata16bits;

  /* Check that a Rx process is ongoing */
  if (huart->RxState == HAL_UART_STATE_BUSY_RX)//判断接收过程是否任然在进行
  {
    if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE))
    {//设置为9位数据而且无校验时的处理
      pdata8bits  = NULL;
      pdata16bits = (uint16_t *) huart->pRxBuffPtr;
      *pdata16bits = (uint16_t)(huart->Instance->DR & (uint16_t)0x01FF);
      huart->pRxBuffPtr += 2U;
    }
    else
    {
      pdata8bits = (uint8_t *) huart->pRxBuffPtr;//
      pdata16bits  = NULL;

      if ((huart->Init.WordLength == UART_WORDLENGTH_9B) || ((huart->Init.WordLength == UART_WORDLENGTH_8B) && (huart->Init.Parity == UART_PARITY_NONE)))
      {//设置为8位数据时无校验或9位数据位时的处理
        *pdata8bits = (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF);//从数据寄存器接收8位数据
      }
      else
      {
        *pdata8bits = (uint8_t)(huart->Instance->DR & (uint8_t)0x007F);//从数据寄存器接收7位数据
      }
      huart->pRxBuffPtr += 1U;//buff指针加一
    }

    if (--huart->RxXferCount == 0U)//此时已经接收了最后一位数据 huart->RxXferCount = 1;
    {//关闭所有中断，设置usart1 的句柄的各个标志位
      /* Disable the UART Data Register not empty Interrupt */
      __HAL_UART_DISABLE_IT(huart, UART_IT_RXNE);

      /* Disable the UART Parity Error Interrupt */
      __HAL_UART_DISABLE_IT(huart, UART_IT_PE);

      /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */
      __HAL_UART_DISABLE_IT(huart, UART_IT_ERR);

      /* Rx process is completed, restore huart->RxState to Ready */
      huart->RxState = HAL_UART_STATE_READY;

      /* Initialize type of RxEvent to Transfer Complete */
      huart->RxEventType = HAL_UART_RXEVENT_TC;

      /* Check current reception Mode :
         If Reception till IDLE event has been selected : */
      if (huart->ReceptionType == HAL_UART_RECEPTION_TOIDLE)
      {//开启了空闲中断，关闭空闲中断
        /* Set reception type to Standard */
        huart->ReceptionType = HAL_UART_RECEPTION_STANDARD;

        /* Disable IDLE interrupt */
        ATOMIC_CLEAR_BIT(huart->Instance->CR1, USART_CR1_IDLEIE);

        /* Check if IDLE flag is set */
        if (__HAL_UART_GET_FLAG(huart, UART_FLAG_IDLE))
        {
          /* Clear IDLE flag in ISR */
          __HAL_UART_CLEAR_IDLEFLAG(huart);
        }
//接收完成，且开启了空闲中断时调用此函数
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
        /*Call registered Rx Event callback*/
        huart->RxEventCallback(huart, huart->RxXferSize);
#else
        /*Call legacy weak Rx Event callback*/
        HAL_UARTEx_RxEventCallback(huart, huart->RxXferSize);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
      }
      else
      {
        /* Standard reception API called */

//接收完成，没有开启空闲中断时选择处理的回调函数
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
        /*Call registered Rx complete callback*/
        huart->RxCpltCallback(huart);
#else
        /*Call legacy weak Rx complete callback*/
        HAL_UART_RxCpltCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
      }

      return HAL_OK;
    }
    return HAL_OK;
  }
  else
  {
    return HAL_BUSY;
  }
}

3、HAL_UART_Receive_IT

判断USART句柄的接收状态，调用UART_Start_Receive_IT 开启中断。

c 复制代码 
HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
{
  /* Check that a Rx process is not already ongoing */
  if (huart->RxState == HAL_UART_STATE_READY)//判断usart状态
  {
    if ((pData == NULL) || (Size == 0U))//判断参数是否有效
    {
      return HAL_ERROR;
    }

    /* Set Reception type to Standard reception */
    huart->ReceptionType = HAL_UART_RECEPTION_STANDARD;//设置接收状态

    return (UART_Start_Receive_IT(huart, pData, Size));//调用接收中断开启函数
  }
  else
  {
    return HAL_BUSY;
  }
}

4、UART_Start_Receive_IT

c 复制代码 
HAL_StatusTypeDef UART_Start_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
{
  huart->pRxBuffPtr = pData;//缓冲区指针初始化
  huart->RxXferSize = Size;//缓冲区大小初始化
  huart->RxXferCount = Size;//接收数据总大小初始化  会在接收时减小

  huart->ErrorCode = HAL_UART_ERROR_NONE;//错误码设置
  huart->RxState = HAL_UART_STATE_BUSY_RX;//接收状态设置

  if (huart->Init.Parity != UART_PARITY_NONE)
  {
    /* Enable the UART Parity Error Interrupt */
    __HAL_UART_ENABLE_IT(huart, UART_IT_PE);
  }
  //开启错误中断和接收中断
  /* Enable the UART Error Interrupt: (Frame error, noise error, overrun error) */
  __HAL_UART_ENABLE_IT(huart, UART_IT_ERR);

  /* Enable the UART Data Register not empty Interrupt */
  __HAL_UART_ENABLE_IT(huart, UART_IT_RXNE);

  return HAL_OK;
}

5、总结

在使用标准库时需要我们先初始化GPIO再初始化USART，然后设置中断优先级并开启中断。在HAL库中，只需要我们初始化GPIO和USART并设置中断优先级，中断的开启和数据的接收都在HAL中封装好了函数，并使用回调函数的方式在接收完成后对数据进行处理。需要注意的是，USART的中断在HAL_UART_Receive_IT中调用UART_Start_Receive_IT开启相关中断，在ISR函数中只需调用HAL_UART_IRQHander函数。每次接收完成后相关的中断都会关闭，需要再次调用HAL_UART_Receive_IT函数开启中断，这也是刚开始用HAL库时常常疑惑的地方，为什么要在初始化时调用一次HAL_UART_Receive_IT函数，在接收完成后的处理函数中要调用HAL_UART_Receive_IT？

当然我们也可以自己调用相关的宏开启中断在ISR中写自己的处理函数，但是这样就不能够调用HAL库提供的函数接收数据了，因为在HAL库中，将外设抽象为句柄，在其中有许多的标志位，我们一旦自己自己调用中断操作后面又使用HAL库的API就会因为外设句柄中的标志位与实际不符而返回错误状态，导致程序卡死。

三、HAL库使用心得

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