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概述

​ 上一篇 说了 STM32CubeMX之串口的使用 (阻塞模式) ，这一章来说说串口中断模式收发数据。

• 开发板：STM32F4探索者（正点原子）

一. 在STM32CubeMX 图形化中开启串口中断

在 前一篇 STM32CubeMX之串口的使用 (阻塞模式) 的文章的基础上，打开串口中断，如下图所示：

然后就可以生成工程了

二. 串口中断相关函数介绍

串口中断函数

• 如串口1中断函数： USART1_IRQHandler()

发送接收函数

• 串口中断模式发送: HAL_UART_Transmit_IT()

HAL_StatusTypeDef HAL_UART_Transmit_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)

1. 串口实例的指针
2. 想要发送的数据的指针，如数组的首地址
3. 想要发送数据的个数

• 串口中断模式接收: HAL_UART_Receive_IT()

HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)

1. 串口实例的指针

2. 接收数据缓冲块的首地址，如数组的首地址

3. 想要接收数据的个数

   ​

相关回调函数

• 串口中断模式发送完成回调: HAL_UART_TxCpltCallback
• 串口中断模式接收完成回调: HAL_UART_RxCpltCallback

三. 串口中断函数使用实例

• 在 stm32f4xx_it.c 中，先看一下串口中断函数有没有添加上，如下图所示：

现在就可以使用中断相关发送接收函数了

在这里为了方便测试,我添加了一个如下结构体并进行了初始化：

• 发送数据

在主函数中，5s 进行一次发送

发送成功产生回调，该函数在main.c 中

然后在主程序中查询到发送成功，打印 send done

• 接收数据

  在进入循环的之前，就说明串口要进行10个字节的数据接收

  

  接收10个字节成功产生回调，该函数在main.c 中

  

  然后在主函数中，查询是否接收成功

  

  最后运行程序，可以在串口调试助手上显示

  

  注意:

  ​ 若定长串口中断接收数据，数据溢出，将会产生数据溢出错误，中断不再接收数据，如下图：

  

  错误回调函数如下：

  //错误回调void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart){
           if( rxtx_it_usart.huart1 == huart)    {
              printf("error %d\r\n",huart->ErrorCode);     }}

  以上例子，代码已上传

  四. HAL库中的串口相关源码介绍

  串口中断函数中的处理函数 HAL_UART_IRQHandler

  /**  * @brief  This function handles UART interrupt request.  * @param  huart  Pointer to a UART_HandleTypeDef structure that contains  *                the configuration information for the specified UART module.  * @retval None  */void HAL_UART_IRQHandler(UART_HandleTypeDef *huart){
         uint32_t isrflags   = READ_REG(huart->Instance->SR);  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));  if (errorflags == RESET)  {
           /* UART in mode Receiver -------------------------------------------------*/    if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))    {
             UART_Receive_IT(huart);      return;    }  }  /* 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);        //  printf("rcv agin error %d\r\n",huart->ErrorCode);      }      /* 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))        {
                 CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAR);          /* Abort the UART DMA Rx stream */          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);          //printf("dma over error \r\n");#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);        //printf("usart over error \r\n");#endif /* USE_HAL_UART_REGISTER_CALLBACKS */        huart->ErrorCode = HAL_UART_ERROR_NONE;      }    }    return;  } /* End if some error occurs */  /* 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;  }}

  主要是分为四个部分：

  • 先读寄存器状态

    uint32_t isrflags   = READ_REG(huart->Instance->SR);  uint32_t cr1its     = READ_REG(huart->Instance->CR1);  uint32_t cr3its     = READ_REG(huart->Instance->CR3);

  • 如果没有错误状态产生，且是接收中断，就进行数据接收

    if (errorflags == RESET)  {
               /* UART in mode Receiver -------------------------------------------------*/    if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))    {
                 UART_Receive_IT(huart);      return;    }  }

  • 错误处理

    //当有parity error,noise error,frame error,Over-Run 错误产生的时候，通过以下回调来处理HAL_UART_ErrorCallback(huart);

    注意：

    ​ 通过查看HAL库，会发现该函数的定义用了关键字__weak (弱符号声明) ,如下：

    __weak void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart){
             /* Prevent unused argument(s) compilation warning */  UNUSED(huart);  /* NOTE: This function should not be modified, when the callback is needed,           the HAL_UART_ErrorCallback could be implemented in the user file   */}

    意味着，它可以由用户自定义函数，如果用户未自定义，否则就使用上述代码

  • 串口数据发送

    • 数据发送

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

      ​

    • 结束数据发送

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

串口中断发送数据函数 HAL_UART_Transmit_IT()

HAL_StatusTypeDef HAL_UART_Transmit_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size){
     /* Check that a Tx process is not already ongoing */  if (huart->gState == HAL_UART_STATE_READY)  {
       if ((pData == NULL) || (Size == 0U))    {
         return HAL_ERROR;    }    /* Process Locked */    __HAL_LOCK(huart);    huart->pTxBuffPtr = pData;    huart->TxXferSize = Size;    huart->TxXferCount = Size;    huart->ErrorCode = HAL_UART_ERROR_NONE;    huart->gState = HAL_UART_STATE_BUSY_TX;    /* Process Unlocked */    __HAL_UNLOCK(huart);    /* Enable the UART Transmit data register empty Interrupt */    __HAL_UART_ENABLE_IT(huart, UART_IT_TXE);    return HAL_OK;  }  else  {
       return HAL_BUSY;  }}

• 对一些状态进行初始化，解释如下

  huart->pTxBuffPtr = pData; //指向我们传递进来的数组huart->TxXferSize = Size;  //要发送数据的个数huart->TxXferCount = Size; //用来计数，未接收数据的个数，发送一个数据就自减，减为0时，发送完成huart->ErrorCode = HAL_UART_ERROR_NONE;huart->gState = HAL_UART_STATE_BUSY_TX;

• 使能当数据寄存器为空时，发生中断

  /* Enable the UART Transmit data register empty Interrupt */    __HAL_UART_ENABLE_IT(huart, UART_IT_TXE);

串口中断接收函数 HAL_UART_Receive_IT

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)  {
       if ((pData == NULL) || (Size == 0U))    {
         return HAL_ERROR;    }    /* Process Locked */    __HAL_LOCK(huart);    huart->pRxBuffPtr = pData;    huart->RxXferSize = Size;    huart->RxXferCount = Size;    huart->ErrorCode = HAL_UART_ERROR_NONE;    huart->RxState = HAL_UART_STATE_BUSY_RX;    /* Process Unlocked */    __HAL_UNLOCK(huart);    /* Enable the UART Parity Error Interrupt */    __HAL_UART_ENABLE_IT(huart, UART_IT_PE);    /* 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;  }  else  {
       return HAL_BUSY;  }}

• 对一些状态进行初始化，解释如下

  huart->pRxBuffPtr = pData; //指针指向接收数据缓冲区，我们传送进来的数组首地址    huart->RxXferSize = Size;  //要接收数据的个数    huart->RxXferCount = Size; //用来计数，未接收数据的个数，接收一个数据就自减，减为0时，接收完成    huart->ErrorCode = HAL_UART_ERROR_NONE;    huart->RxState = HAL_UART_STATE_BUSY_RX;

• 使能 校验错误中断，帧错误，噪声错误中断，数据溢出中断

  /* Enable the UART Parity Error Interrupt */    __HAL_UART_ENABLE_IT(huart, UART_IT_PE);    /* 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);

  ​后续还会继续分享串口的其他基础知识和使用，感兴趣的小伙伴记得关注我！

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