USART DMA

串口使用DMA的方式来接收数据和发送数据。

参考官方的工程文件，文件位置记录一下：

Z:\2022-YS\YH-F407-Guang-fang-lib\STM32Cube_FW_F4_V1.27.1\Projects\STM32F401-Discovery\Examples\UART\UART_TwoBoards_ComIT

1.串口和DMA初始化

/**
  * Enable DMA controller clock
  */
void MX_DMA_Init(void)
{

  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();

  /* DMA interrupt init */
  /* DMA1_Stream5_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream5_IRQn, 5, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream5_IRQn);
  /* DMA1_Stream6_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream6_IRQn, 5, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream6_IRQn);

}

/* USART2 init function */

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 */

  /* USER CODE END USART2_Init 2 */

}

2.任务函数中进行数据的接收和发送

/******************************************************************************
* PUBLIC FUNCTIONS
******************************************************************************/
void StartTask02(void *argument)
{
	
  /* USER CODE BEGIN StartTask02 */
  /* Infinite loop */
  for(;;)
  {	
	#if 1
	RS485_RX;
	osStatus_t status;
	HAL_UART_Receive_DMA(&huart2, recv_buf, 30);
	// 等待接收一帧数据的信号量的到来
	status = osSemaphoreAcquire (myBinarySem_recvHandle, 5000);
	if(status == osOK)
	{
		// 获得一个接收一帧数据的信号量
		// 可以在这里解析这一帧数据
		#if 1
		RS485_TX;
		uint8_t hello_01[] = "hello world #######&&&&!\r\n";
		//uint8_t hello_01[] = "hello world #######&&&&!"; // 2024-08-09 是测试的电路板有问题，USART2只能接收不能发送
		HAL_UART_Transmit_DMA(&huart2, &hello_01[0], sizeof(hello_01));
		#endif
	}
	// 开始发送一帧数据回去
	#if 0
	RS485_TX;
	uint8_t hello_01[] = "hello world #######&&&& osSemaphoreAcquireHAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)!\r\n";
	HAL_UART_Transmit_DMA(&huart2, hello_01, sizeof(hello_01));
	#endif
	// 等待发送一帧数据完成的信号量的到来
	status = osSemaphoreAcquire (myBinarySem_sendHandle, 5000);
	if(status == osOK)
	{
		// 说明一帧数据发送完成，可以从头来过继续接收一帧数据的到来了
	}
	#endif
	LED_S7_TOG;
    osDelay(20);// 提高执行的频率
  }
  /* USER CODE END StartTask02 *

3. 回调函数中释放信号量

/*Call legacy weak Tx complete callback*/
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
	//LED_S1_TOG;
	osStatus_t status;
	status = osSemaphoreRelease(myBinarySem_sendHandle);
	if(status != osOK)
	{}
}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	//LED_S3_TOG;
	osStatus_t status;
	status = osSemaphoreRelease(myBinarySem_recvHandle);
	if(status != osOK)
	{}
}

4. 任务函数中，接收一帧数据，然后发送一帧数据，实验效果如下图：