STM32F412RET6使用DMA收发数据程序

以下是使用DMA收发数据的示例程序，包括了初始化、发送和接收的函数实现。

首先，需要初始化USART和DMA：

void USART_DMA_Init(void)
{
    DMA_HandleTypeDef hdma_usart_tx;
    DMA_HandleTypeDef hdma_usart_rx;

    // Enable DMA2 clock
    __HAL_RCC_DMA2_CLK_ENABLE();

    // Enable USART1 clock
    __HAL_RCC_USART1_CLK_ENABLE();

    // Configure DMA for USART1 TX
    hdma_usart_tx.Instance = DMA2_Stream7;
    hdma_usart_tx.Init.Channel = DMA_CHANNEL_4;
    hdma_usart_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_usart_tx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart_tx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart_tx.Init.Mode = DMA_NORMAL;
    hdma_usart_tx.Init.Priority = DMA_PRIORITY_LOW;
    hdma_usart_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    HAL_DMA_Init(&hdma_usart_tx);

    // Associate the initialized DMA handle to the USART handle
    __HAL_LINKDMA(&huart1, hdmatx, hdma_usart_tx);

    // Configure DMA for USART1 RX
    hdma_usart_rx.Instance = DMA2_Stream2;
    hdma_usart_rx.Init.Channel = DMA_CHANNEL_4;
    hdma_usart_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_usart_rx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart_rx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart_rx.Init.Mode = DMA_CIRCULAR;
    hdma_usart_rx.Init.Priority = DMA_PRIORITY_HIGH;
    hdma_usart_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    HAL_DMA_Init(&hdma_usart_rx);

    // Associate the initialized DMA handle to the USART handle
    __HAL_LINKDMA(&huart1, hdmarx, hdma_usart_rx);

    // Enable DMA transfer complete interrupt
    __HAL_DMA_ENABLE_IT(&hdma_usart_rx, DMA_IT_TC);

    // Enable USART1 global interrupt
    HAL_NVIC_SetPriority(USART1_IRQn, 1, 1);
    HAL_NVIC_EnableIRQ(USART1_IRQn);
}

然后，需要实现发送函数：

void USART_DMA_Send(uint8_t *pData, uint16_t Size)
{
    // Wait for DMA TX buffer to be ready
    while (HAL_DMA_GetState(huart1.hdmatx) != HAL_DMA_STATE_READY);

    // Disable DMA TX stream transfer
    __HAL_DMA_DISABLE(huart1.hdmatx);

    // Configure DMA TX stream transfer
    HAL_DMA_Start_IT(huart1.hdmatx, (uint32_t)pData, (uint32_t)&huart1.Instance->DR, Size);

    // Enable DMA TX stream transfer
    __HAL_DMA_ENABLE(huart1.hdmatx);
}

最后，需要实现接收函数：

void USART_DMA_Receive(uint8_t *pData, uint16_t Size)
{
    // Wait for DMA RX buffer to be ready
    while (HAL_DMA_GetState(huart1.hdmarx) != HAL_DMA_STATE_READY);

    // Disable DMA RX stream transfer
    __HAL_DMA_DISABLE(huart1.hdmarx);

    // Configure DMA RX stream transfer
    HAL_DMA_Start_IT(huart1.hdmarx, (uint32_t)&huart1.Instance->DR, (uint32_t)pData, Size);

    // Enable DMA RX stream transfer
    __HAL_DMA_ENABLE(huart1.hdmarx);

    // Enable USART1
    HAL_UART_Receive_IT(&huart1, pData, Size);
}

以上就是使用DMA收发数据的示例程序。需要注意的是，我们使用了循环DMA模式来接收数据，并启用了DMA传输完成中断。这样可以保证在接收到指定长度的数据后，及时通知CPU进行处理。同时，在发送数据时，我们需要等待DMA传输完成后再进行下一次传输。