（stm32f4 HAL）各位大神啊，请告诉我 串口接收中这段代码的意思

胡图图

/**
  * @brief  Receives an amount of data in non blocking mode
  * @param  huart: pointer to a UART_HandleTypeDef structure that contains
  *                the configuration information for the specified UART module.
  * @retval HAL status
  */
static HAL_StatusTypeDef UART_Receive_IT(UART_HandleTypeDef *huart)
{
  uint16_t* tmp;

  /* Check that a Rx process is ongoing */
  if(huart->RxState == HAL_UART_STATE_BUSY_RX)
  {
    if(huart->Init.WordLength == UART_WORDLENGTH_9B)
    {
      tmp = (uint16_t*) huart->pRxBuffPtr;
      if(huart->Init.Parity == UART_PARITY_NONE)
      {
        *tmp = (uint16_t)(huart->Instance->DR & (uint16_t)0x01FFU);
        huart->pRxBuffPtr += 2U;
      }
      else
      {
        *tmp = (uint16_t)(huart->Instance->DR & (uint16_t)0x00FFU);
        huart->pRxBuffPtr += 1U;
      }
    }
    else
    {
      if(huart->Init.Parity == UART_PARITY_NONE)
      {
        *huart->pRxBuffPtr++ = (uint8_t)(huart->Instance->DR & (uint8_t)0x00FFU);
      }
      else
      {
        *huart->pRxBuffPtr++ = (uint8_t)(huart->Instance->DR & (uint8_t)0x007FU);
      }
    }

    if(--huart->RxXferCount == 0U)
    {
      /* Disable the UART Parity Error Interrupt and RXNE interrupt*/
      CLEAR_BIT(huart->Instance->CR1, (USART_CR1_RXNEIE | USART_CR1_PEIE));

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

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

      HAL_UART_RxCpltCallback(huart);

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


那个解释下呗。。

cancore

U表示无符号整形，+2的意思是如果串口字长为9bit则占两个字节，所以指针加2，对应取值是0x01FF;同理如果是8bit以下则占一个字节，指针加1，对应取值是0x00FF

胡图图

cancore 发表于 2017-8-21 16:28
U表示无符号整形，+2的意思是如果串口字长为9bit则占两个字节，所以指针加2，对应取值是0x01FF;同理如果是8 ...

谢谢大佬，大概明白了

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