[嵌入式]STM32H7串口DMA空闲中断收发不定长数据

源码链接：STM32H7串口DMA空闲中断收发不定长数据_Code
视频链接：STM32H7串口DMA空闲中断收发不定长数据
串口中断：串口中断使用的比较多，收到一个字节的数据就进入一次中断，这样每一个字节都需要进入中断，这样就大大增加了CPU的负荷。
串口DMA：在使用串口DMA时候，会大大降低CPU的负荷，数据的传输会直接通过DMA传输，不需要CPU的干预，但是在接收数据的时候，接收的数据是固定长度的，如果需要接收不定长数据的话就需要添加很多软件代码来判断数据是否接收完成，比较复杂。
串口DAM+空闲中断：在串口使用DMA时候同时使用空闲中断，这样就可以接收不定长数据，并且还可以记录接收到的数据长度，这样不仅可以减小CPU的负荷，还可以简化代码的复杂程度
部分核心代码如下：

void MX_USART1_UART_Init(void)
{
  huart1.Instance                    = USART1;
  huart1.Init.BaudRate               = 115200;
  huart1.Init.WordLength             = UART_WORDLENGTH_8B;
  huart1.Init.StopBits               = UART_STOPBITS_1;
  huart1.Init.Parity                 = UART_PARITY_NONE;
  huart1.Init.Mode                   = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl              = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling           = UART_OVERSAMPLING_16;
  huart1.Init.OneBitSampling         = UART_ONE_BIT_SAMPLE_DISABLE;
  huart1.Init.ClockPrescaler         = UART_PRESCALER_DIV1;
  huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetTxFifoThreshold(&huart1, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetRxFifoThreshold(&huart1, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_DisableFifoMode(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  __HAL_UART_ENABLE_IT(&huart1,UART_IT_IDLE);
  HAL_UART_Receive_DMA(&huart1, RxBuffer, RxBufferSize);
}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
  if(uartHandle->Instance==USART1)
  {
    PeriphClkInitStruct.PeriphClockSelection  = RCC_PERIPHCLK_USART1;
    PeriphClkInitStruct.Usart16ClockSelection = RCC_USART16CLKSOURCE_D2PCLK2;
    if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
    {
      Error_Handler();
    }
    __HAL_RCC_USART1_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**USART1 GPIO Configuration
    PA10     ------> USART1_RX
    PA9     ------> USART1_TX
    */
    GPIO_InitStruct.Pin       = GPIO_PIN_10|GPIO_PIN_9;
    GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull      = GPIO_PULLUP;
    GPIO_InitStruct.Speed     = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    /* USART1 DMA Init */
    /* USART1_RX Init */
    hdma_usart1_rx.Instance                 = DMA1_Stream0;
    hdma_usart1_rx.Init.Request             = DMA_REQUEST_USART1_RX;
    hdma_usart1_rx.Init.Direction           = DMA_PERIPH_TO_MEMORY;
    hdma_usart1_rx.Init.PeriphInc           = DMA_PINC_DISABLE;
    hdma_usart1_rx.Init.MemInc              = DMA_MINC_ENABLE;
    hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart1_rx.Init.MemDataAlignment    = DMA_MDATAALIGN_BYTE;
    hdma_usart1_rx.Init.Mode                = DMA_CIRCULAR;
    hdma_usart1_rx.Init.Priority            = DMA_PRIORITY_LOW;
    hdma_usart1_rx.Init.FIFOMode            = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK)
    {
      Error_Handler();
    }
    __HAL_LINKDMA(uartHandle,hdmarx,hdma_usart1_rx);
    /* USART1_TX Init */
    hdma_usart1_tx.Instance                 = DMA1_Stream1;
    hdma_usart1_tx.Init.Request             = DMA_REQUEST_USART1_TX;
    hdma_usart1_tx.Init.Direction           = DMA_MEMORY_TO_PERIPH;
    hdma_usart1_tx.Init.PeriphInc           = DMA_PINC_DISABLE;
    hdma_usart1_tx.Init.MemInc              = DMA_MINC_ENABLE;
    hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart1_tx.Init.MemDataAlignment    = DMA_MDATAALIGN_BYTE;
    hdma_usart1_tx.Init.Mode                = DMA_NORMAL;
    hdma_usart1_tx.Init.Priority            = DMA_PRIORITY_LOW;
    hdma_usart1_tx.Init.FIFOMode            = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK)
    {
      Error_Handler();
    }
    __HAL_LINKDMA(uartHandle,hdmatx,hdma_usart1_tx);

    HAL_NVIC_SetPriority(USART1_IRQn, 1, 0);
    HAL_NVIC_EnableIRQ(USART1_IRQn);
  }
}

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
	if(huart->Instance == USART1)
	{
		HAL_UART_Receive_DMA(&huart1, RxBuffer, RxBufferSize);
		RxNum = 0;
		memset(RxBuffer,0,RxBufferSize);
	}
}

void USART1_IRQHandler(void)
{
  if(__HAL_UART_GET_FLAG(&huart1,UART_FLAG_IDLE) == SET)
  {
	  __HAL_UART_CLEAR_IDLEFLAG(&huart1);
	  HAL_UART_DMAStop(&huart1);
	  RxNum = RxBufferSize - __HAL_DMA_GET_COUNTER(&hdma_usart1_rx);
	  HAL_UART_Transmit_DMA(&huart1, RxBuffer, RxNum);
  }
  HAL_UART_IRQHandler(&huart1);
}