使用USART2，波特率115200
1、配置引脚
2、配置串口参数：波特率、校验位、停止位等
?
?3、使能中断
4、配置时钟，SYSCLK=168MHz
5、生成代码，生成代码后需要在串口初始化函数中以及接收回调函数中添加 开启接收中断 语句：
/**
* @brief Receives an amount of data in non blocking mode.
* @note When UART parity is not enabled (PCE = 0), and Word Length is configured to 9 bits (M1-M0 = 01),
* the received data is handled as a set of u16. In this case, Size must indicate the number
* of u16 available through pData.
* @param huart Pointer to a UART_HandleTypeDef structure that contains
* the configuration information for the specified UART module.
* @param pData Pointer to data buffer (u8 or u16 data elements).
* @param Size Amount of data elements (u8 or u16) to be received.
* @retval HAL status
*/
HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)?首先添加接收数据数组，用以保存串口接收数据，长度根据需要自定义
/* Buffer used for reception */
uint8_t aRxBuffer[20];在串口初始化的结尾加上?开启接收中断
/**
* @brief USART2 Initialization Function
* @param None
* @retval None
*/
static void MX_USART2_UART_Init(void)
{
/* USER CODE BEGIN USART2_Init 0 */
/* USER CODE END USART2_Init 0 */
/* USER CODE BEGIN USART2_Init 1 */
/* USER CODE END USART2_Init 1 */
huart2.Instance = USART2;
huart2.Init.BaudRate = 115200;
huart2.Init.WordLength = UART_WORDLENGTH_8B;
huart2.Init.StopBits = UART_STOPBITS_1;
huart2.Init.Parity = UART_PARITY_NONE;
huart2.Init.Mode = UART_MODE_TX_RX;
huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart2.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART2_Init 2 */
HAL_UART_Receive_IT(&huart2, (uint8_t *)aRxBuffer, 1);
/* USER CODE END USART2_Init 2 */
}在接收回调函数的结尾加上?开启接收中断并将接收到的数据通过串口返回
__weak void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(huart);
HAL_UART_Transmit(&huart2,(uint8_t *)aRxBuffer,1,0xFFFF);
HAL_UART_Receive_IT(&huart2, (uint8_t *)aRxBuffer, 1);
/* NOTE: This function should not be modified, when the callback is needed,
the HAL_UART_RxCpltCallback could be implemented in the user file
*/
}