UART使用DMA和循环队列接收数据的代码

以下是使用DMA和循环队列接收UART数据的示例代码：

#include "stm32f4xx_hal.h"

#define UART_RX_BUF_SIZE 256

UART_HandleTypeDef huart;
DMA_HandleTypeDef hdma_usart_rx;

uint8_t uart_rx_buf[UART_RX_BUF_SIZE];
volatile uint16_t uart_rx_head = 0;
volatile uint16_t uart_rx_tail = 0;

void HAL_UART_MspInit(UART_HandleTypeDef *huart)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};
    if (huart->Instance == USART1)
    {
        /* Peripheral clock enable */
        __HAL_RCC_USART1_CLK_ENABLE();

        __HAL_RCC_GPIOB_CLK_ENABLE();
        /**USART1 GPIO Configuration
        PB6     ------> USART1_TX
        PB7     ------> USART1_RX
        */
        GPIO_InitStruct.Pin = GPIO_PIN_6 | GPIO_PIN_7;
        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
        GPIO_InitStruct.Pull = GPIO_PULLUP;
        GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
        GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
        HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

        /* USART1 DMA Init */
        /* USART1_RX Init */
        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_LOW;
        hdma_usart_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
        if (HAL_DMA_Init(&hdma_usart_rx) != HAL_OK)
        {
            Error_Handler();
        }

        __HAL_LINKDMA(huart, hdmarx, hdma_usart_rx);

        /* USART1 interrupt Init */
        HAL_NVIC_SetPriority(USART1_IRQn, 0, 0);
        HAL_NVIC_EnableIRQ(USART1_IRQn);
    }
}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    if (huart->Instance == USART1)
    {
        // Move tail pointer to next position
        uart_rx_tail = (uart_rx_tail + 1) % UART_RX_BUF_SIZE;
    }
}

void USART1_IRQHandler(void)
{
    HAL_UART_IRQHandler(&huart);
}

void uart_init(void)
{
    huart.Instance = USART1;
    huart.Init.BaudRate = 115200;
    huart.Init.WordLength = UART_WORDLENGTH_8B;
    huart.Init.StopBits = UART_STOPBITS_1;
    huart.Init.Parity = UART_PARITY_NONE;
    huart.Init.Mode = UART_MODE_TX_RX;
    huart.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    huart.Init.OverSampling = UART_OVERSAMPLING_16;
    if (HAL_UART_Init(&huart) != HAL_OK)
    {
        Error_Handler();
    }
}

void dma_init(void)
{
    __HAL_RCC_DMA2_CLK_ENABLE();

    HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
}

void DMA2_Stream2_IRQHandler(void)
{
    HAL_DMA_IRQHandler(&hdma_usart_rx);
}

void start_uart_dma_rx(void)
{
    HAL_UART_Receive_DMA(&huart, uart_rx_buf, UART_RX_BUF_SIZE);
}

uint8_t uart_rx_buf_pop(void)
{
    uint8_t data = uart_rx_buf[uart_rx_head];
    uart_rx_head = (uart_rx_head + 1) % UART_RX_BUF_SIZE;
    return data;
}

uint16_t uart_rx_buf_size(void)
{
    if (uart_rx_head <= uart_rx_tail)
    {
        return uart_rx_tail - uart_rx_head;
    }
    else
    {
        return UART_RX_BUF_SIZE - (uart_rx_head - uart_rx_tail);
    }
}

int main(void)
{
    HAL_Init();
    uart_init();
    dma_init();
    start_uart_dma_rx();

    while (1)
    {
        if (uart_rx_buf_size() > 0)
        {
            uint8_t data = uart_rx_buf_pop();
            // Process received data
        }
    }
}

在上述代码中，我们使用 HAL 库来初始化 UART 和 DMA。我们使用循环队列来存储接收到的 UART 数据，这样可以避免数据丢失和覆盖。我们还实现了一个简单的 API 来访问循环队列中的数据。

在 `main()` 函数中，我们不断检查循环队列中是否有接收到的数据，并进行处理。当收到新数据时，我们将它从循环队列中弹出并进行处理。