STM32H7 串口 空闲中断 任意长接收 Hal库 IDLE

今天主要记录一下STM32H7系列串口的使用，正点原子、野火等各大家都有教程，当然用起来也没有问题。

解决方法后边有红色大字提醒，直接看后边就可以，如果你没有时间想去了解HAL库的接收思想。

ST推的HAL库，在整个接收过程中，是没有用到串口的接收空闲中断，它的处理有三种，分别是轮询，接收完成中断（每一个字节一次），DMA接收。

整个Hal库把接收和发送过程都封装好了，就用最简单的轮询方式看，先看库函数代码：

/**
  * @brief Receive an amount of data in blocking mode.
  * @note When FIFO mode is enabled, the RXFNE flag is set as long as the RXFIFO
  *       is not empty. Read operations from the RDR register are performed when
  *       RXFNE flag is set. From hardware perspective, RXFNE flag and
  *       RXNE are mapped on the same bit-field.
  * @param huart   UART handle.
  * @param pData   Pointer to data buffer.
  * @param Size    Amount of data to be received.
  * @param Timeout Timeout duration.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_UART_Receive(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
  uint8_t  *pdata8bits;
  uint16_t *pdata16bits;
  uint16_t uhMask;
  uint32_t tickstart;

  /* 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->ErrorCode = HAL_UART_ERROR_NONE;
    huart->RxState = HAL_UART_STATE_BUSY_RX;

    /* Init tickstart for timeout managment*/
    tickstart = HAL_GetTick();

    huart->RxXferSize  = Size;
    huart->RxXferCount = Size;

    /* Computation of UART mask to apply to RDR register */
    UART_MASK_COMPUTATION(huart);
    uhMask = huart->Mask;

    /* In case of 9bits/No Parity transfer, pRxData needs to be handled as a uint16_t pointer */
    if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE))
    {
      pdata8bits  = NULL;
      pdata16bits = (uint16_t *) pData;
    }
    else
    {
      pdata8bits  = pData;
      pdata16bits = NULL;
    }

    /* as long as data have to be received */
    while (huart->RxXferCount > 0U)
    {
      if (UART_WaitOnFlagUntilTimeout(huart, UART_FLAG_RXNE, RESET, tickstart, Timeout) != HAL_OK)
      {
        return HAL_TIMEOUT;
      }
      if (pdata8bits == NULL)
      {
        *pdata16bits = (uint16_t)(huart->Instance->RDR & uhMask);
        pdata16bits++;
      }
      else
      {
        *pdata8bits = (uint8_t)(huart->Instance->RDR & (uint8_t)uhMask);
        pdata8bits++;
      }
      huart->RxXferCount--;
    }

    /* At end of Rx process, restore huart->RxState to Ready */
    huart->