stm32 uart dma 同时发送接收程序

以下是一个简单的示例程序，展示了如何使用DMA同时实现STM32的UART发送和接收：

#include "stm32f4xx.h"

#define UART_BUFFER_SIZE 32

uint8_t tx_buffer[UART_BUFFER_SIZE];
uint8_t rx_buffer[UART_BUFFER_SIZE];

void uart_init(void)
{
    GPIO_InitTypeDef gpio_init;
    USART_InitTypeDef usart_init;
    DMA_InitTypeDef dma_init;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

    gpio_init.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
    gpio_init.GPIO_Mode = GPIO_Mode_AF;
    gpio_init.GPIO_Speed = GPIO_Speed_50MHz;
    gpio_init.GPIO_OType = GPIO_OType_PP;
    gpio_init.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOA, &gpio_init);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);

    usart_init.USART_BaudRate = 115200;
    usart_init.USART_WordLength = USART_WordLength_8b;
    usart_init.USART_StopBits = USART_StopBits_1;
    usart_init.USART_Parity = USART_Parity_No;
    usart_init.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    usart_init.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART2, &usart_init);

    dma_init.DMA_Channel = DMA_Channel_4;
    dma_init.DMA_PeripheralBaseAddr = (uint32_t)&(USART2->DR);
    dma_init.DMA_Memory0BaseAddr = (uint32_t)tx_buffer;
    dma_init.DMA_DIR = DMA_DIR_MemoryToPeripheral;
    dma_init.DMA_BufferSize = UART_BUFFER_SIZE;
    dma_init.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    dma_init.DMA_MemoryInc = DMA_MemoryInc_Enable;
    dma_init.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    dma_init.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    dma_init.DMA_Mode = DMA_Mode_Normal;
    dma_init.DMA_Priority = DMA_Priority_Medium;
    dma_init.DMA_FIFOMode = DMA_FIFOMode_Disable;
    dma_init.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    dma_init.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    dma_init.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA1_Stream6, &dma_init);

    dma_init.DMA_Channel = DMA_Channel_4;
    dma_init.DMA_PeripheralBaseAddr = (uint32_t)&(USART2->DR);
    dma_init.DMA_Memory0BaseAddr = (uint32_t)rx_buffer;
    dma_init.DMA_DIR = DMA_DIR_PeripheralToMemory;
    dma_init.DMA_BufferSize = UART_BUFFER_SIZE;
    dma_init.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    dma_init.DMA_MemoryInc = DMA_MemoryInc_Enable;
    dma_init.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    dma_init.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    dma_init.DMA_Mode = DMA_Mode_Normal;
    dma_init.DMA_Priority = DMA_Priority_Medium;
    dma_init.DMA_FIFOMode = DMA_FIFOMode_Disable;
    dma_init.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    dma_init.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    dma_init.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA1_Stream5, &dma_init);

    USART_DMACmd(USART2, USART_DMAReq_Tx | USART_DMAReq_Rx, ENABLE);

    DMA_Cmd(DMA1_Stream6, DISABLE);
    DMA_ITConfig(DMA1_Stream6, DMA_IT_TC, ENABLE);

    DMA_Cmd(DMA1_Stream5, DISABLE);
    DMA_ITConfig(DMA1_Stream5, DMA_IT_TC, ENABLE);

    USART_Cmd(USART2, ENABLE);
}

void uart_send(uint8_t *buffer, uint16_t size)
{
    while (DMA_GetCmdStatus(DMA1_Stream6) != DISABLE);

    DMA_ClearFlag(DMA1_Stream6, DMA_FLAG_TCIF6);

    memcpy(tx_buffer, buffer, size);

    DMA_SetCurrDataCounter(DMA1_Stream6, size);
    DMA_Cmd(DMA1_Stream6, ENABLE);
}

void uart_receive(uint8_t *buffer, uint16_t size)
{
    while (DMA_GetCmdStatus(DMA1_Stream5) != DISABLE);

    DMA_ClearFlag(DMA1_Stream5, DMA_FLAG_TCIF5);

    DMA_SetCurrDataCounter(DMA1_Stream5, size);
    DMA_Cmd(DMA1_Stream5, ENABLE);

    while (DMA_GetCmdStatus(DMA1_Stream5) != DISABLE);

    memcpy(buffer, rx_buffer, size);
}

int main(void)
{
    uint8_t buffer[UART_BUFFER_SIZE];

    uart_init();

    while (1)
    {
        // 从UART接收数据
        uart_receive(buffer, UART_BUFFER_SIZE);

        // 处理接收到的数据

        // 发送数据到UART
        uart_send(buffer, UART_BUFFER_SIZE);
    }
}

该程序使用了DMA来传输数据，因此发送和接收过程都是异步的。在主函数中，我们可以反复调用“uart_receive”和“uart_send”函数，以便在UART上进行无缝通信。请注意，这只是一个简单的示例程序，您可能需要进行一些修改才能满足您的特定需求。