stm32 uart dma 同时接收发送程序

以下是一个基于STM32的UART DMA同时接收和发送的示例程序：

#include "stm32f10x.h"
#include <stdio.h>
#include <string.h>

#define BUFFER_SIZE 100

uint8_t rx_buffer[BUFFER_SIZE];
uint8_t tx_buffer[BUFFER_SIZE];

void dma_init(void)
{
    DMA_InitTypeDef DMA_InitStructure;

    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

    DMA_DeInit(DMA1_Channel4);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)tx_buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    DMA_InitStructure.DMA_BufferSize = BUFFER_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel4, &DMA_InitStructure);

    DMA_DeInit(DMA1_Channel5);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)rx_buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_BufferSize = BUFFER_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel5, &DMA_InitStructure);

    USART_DMACmd(USART1, USART_DMAReq_Tx | USART_DMAReq_Rx, ENABLE);

    DMA_Cmd(DMA1_Channel4, ENABLE);
    DMA_Cmd(DMA1_Channel5, ENABLE);
}

void uart_init(void)
{
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    USART_InitStructure.USART_BaudRate = 115200;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    USART_Cmd(USART1, ENABLE);
}

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

    while (1) {
        if (USART_GetFlagStatus(USART1, USART_FLAG_TC) == SET) {
            DMA_Cmd(DMA1_Channel4, DISABLE);
            memcpy(tx_buffer, rx_buffer, BUFFER_SIZE);
            DMA_SetCurrDataCounter(DMA1_Channel4, BUFFER_SIZE);
            DMA_Cmd(DMA1_Channel4, ENABLE);
        }
    }
}

这个程序实现了UART的循环DMA接收和DMA发送功能。在初始化函数`dma_init()`中，配置了DMA通道4和DMA通道5，分别用于UART的DMA发送和DMA接收。在主函数中，通过判断UART的发送完成标志位，来触发DMA传输，并将接收到的数据复制到发送缓冲区中，实现了循环DMA传输的功能。需要注意的是，在实际应用中，可能需要根据具体的需求对DMA传输模式和中断处理方式进行调整。