STM32F407 串口DMA接收数据的实例

以下是一个基于STM32F407芯片的串口DMA接收数据的实例代码：

#include "stm32f4xx.h"
#include <stdio.h>
#include <string.h>

#define USART1_DR_Address ((uint32_t)0x40011004)

char RxBuffer[64];
uint8_t RxCounter = 0;
uint8_t RxFlag = 0;

void USART_Config(void);
void DMA_Config(void);

int main(void)
{
    USART_Config();
    DMA_Config();

    while(1)
    {
        if(RxFlag)
        {
            printf("Received data: %s\r\n", RxBuffer);
            RxFlag = 0;
            memset(RxBuffer, 0, sizeof(RxBuffer));
            RxCounter = 0;
        }
    }
}

void USART_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    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);
}

void DMA_Config(void)
{
    DMA_InitTypeDef DMA_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);

    DMA_DeInit(DMA2_Stream2);

    DMA_InitStructure.DMA_Channel = DMA_Channel_4;
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)USART1_DR_Address;
    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)RxBuffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStructure.DMA_BufferSize = sizeof(RxBuffer);
    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_FIFOMode = DMA_FIFOMode_Disable;
    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA2_Stream2, &DMA_InitStructure);

    DMA_ITConfig(DMA2_Stream2, DMA_IT_TC, ENABLE);

    NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);

    DMA_Cmd(DMA2_Stream2, ENABLE);
}

void DMA2_Stream2_IRQHandler(void)
{
    if(DMA_GetITStatus(DMA2_Stream2, DMA_IT_TCIF2))
    {
        DMA_ClearITPendingBit(DMA2_Stream2, DMA_IT_TCIF2);
        RxCounter = sizeof(RxBuffer) - DMA_GetCurrDataCounter(DMA2_Stream2);
        RxBuffer[RxCounter] = '\0';
        RxFlag = 1;
    }
}

在这个例子中，我们使用USART1和DMA2_Stream2来接收串口数据。首先，在USART_Config函数中，我们进行了USART的配置，将USART1的TX和RX引脚分别配置为PA9和PA10，并设置波特率为115200。

接下来，在DMA_Config函数中，我们对DMA进行了配置。我们将DMA的通道设置为4，将DMA的方向设置为从外设到内存，并将DMA的模式设置为循环模式。我们还启用了DMA的中断，并将DMA2_Stream2_IRQHandler函数作为中断处理函数。

最后，在DMA2_Stream2_IRQHandler函数中，我们检查DMA传输完成中断标志位，并清除该标志位。然后，我们通过DMA_GetCurrDataCounter函数计算已经接收到的数据量，并将RxFlag设置为1，表示已经接收到了一条完整的数据。

在主函数中，我们不断地检查RxFlag标志位，如果该标志位为1，则表示已经接收到了一条完整的数据，我们将其打印出来，并将RxFlag和RxBuffer数组清零。