__weak void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)

这是一个 HAL 库中 UART 接收完成回调函数的声明，用于在 UART 接收完成后执行指定操作。其中，`__weak` 是弱化链接指令，用于定义一个可被覆盖的弱符号。`HAL_UART_RxCpltCallback` 函数会在 HAL 库中的 UART 接收完成中被调用，执行 UART 接收完成后需要进行的操作，例如解析接收到的数据。函数参数 `huart` 是一个指向 UART 句柄的指针，可以用于获取相关的 UART 配置信息和接收数据。

相关问题

2604: __weak void HAL_UART_TxHalfCpltCallback(UART_HandleTypeDef *huart)

This function is a weak callback function in the HAL UART driver library for STM32 microcontrollers. It is called by the driver when a UART transmission buffer has been half-transmitted. The "weak" attribute means that if the user does not define this function in their code, a default implementation will be provided by the library.

You can use this callback to perform certain actions when the UART transmission buffer has been half-transmitted, such as starting to fill the buffer with new data.

STM32F407 HAL库uart发送函数

以下是STM32F407 HAL库uart发送函数的示例代码：

/**
  * @brief  Sends an amount of data through the UARTx peripheral.
  * @param  huart: UART handle.
  * @param  pData: Pointer to data buffer.
  * @param  Size: Amount of data to be sent.
  * @retval HAL status.
  */
HAL_StatusTypeDef HAL_UART_Transmit(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
  uint16_t* tmp;
  uint16_t uhMask;
  uint32_t tickstart = 0U;

  /* Check that a Tx process is not already ongoing */
  if(huart->gState == HAL_UART_STATE_READY)
  {
    /* Compile time check if possible */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
    /* Call registered Tx complete callback */
    huart->TxCpltCallback(huart);
#else
    /* Tx transfer start */
    huart->gState = HAL_UART_STATE_BUSY_TX;
#endif  /* USE_HAL_UART_REGISTER_CALLBACKS */

    huart->ErrorCode = HAL_UART_ERROR_NONE;
    if(huart->Init.WordLength == UART_WORDLENGTH_9B)
    {
      if(huart->Init.Parity == UART_PARITY_NONE)
      {
        tmp = (uint16_t*) pData;
        uhMask = 0x01FFU; /* 9 bits */
      }
      else
      {
        tmp = (uint16_t*) pData;
        uhMask = 0x00FFU; /* 8 bits + parity */
      }
    }
    else
    {
      tmp = (uint16_t*) pData;
      uhMask = 0x007FU; /* 7 bits */
    }

    huart->TxXferCount = Size;
    /* To avoid building warning message */
    /* (__GNUC__ compiler: cast between incompatible function types) */
    /* cast pData to uint16_t* in case of 9bits or 8bits + parity format */
    huart->pTxBuffPtr = (uint8_t*)(tmp);
    huart->TxXferSize = Size;
    /* Process Locked */
    __HAL_LOCK(huart);

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

    tickstart = HAL_GetTick();

    while(huart->TxXferCount > 0U)
    {
      if((Timeout == 0U) || ((HAL_GetTick()-tickstart) > Timeout))
      {
        huart->gState = HAL_UART_STATE_TIMEOUT;
        /* Process Unlocked */
        __HAL_UNLOCK(huart);
        return HAL_TIMEOUT;
      }
    }

    /* At end of Tx process, restore huart->pTxBuffPtr and huart->TxXferSize
      (could have been changed during Tx process) */
    huart->pTxBuffPtr = pData;
    huart->TxXferSize = Size;

    /* Disable the UART Transmit data register empty Interrupt */
    __HAL_UART_DISABLE_IT(huart, UART_IT_TXE);

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

    /* Process Unlocked */
    __HAL_UNLOCK(huart);

    /* Call Tx complete callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
    /* Call registered Tx complete callback */
    huart->TxCpltCallback(huart);
#else
    /* Call legacy weak Tx complete callback */
    HAL_UART_TxCpltCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */

    return HAL_OK;
  }
  else
  {
    return HAL_BUSY;
  }
}

此函数将发送数据缓冲区指针，要发送的数据大小和超时作为参数。在调用此函数之前，必须先初始化UART外设和使用HAL_UART_MspInit()函数配置外设时钟、GPIO等引脚。在发送数据之后，可以使用回调函数处理传输完成事件，或者使用轮询检查状态。在数据传输期间，数据将通过UART外设发送，并在传输完成后通过回调函数或轮询调用进行通知。如果传输过程中超时，函数将返回HAL_TIMEOUT状态。