基于stm32F407 串口2 采用DMA方式接收数据，请给我具体代码

### 回答1：
在 stm32F407 微控制器上，使用 DMA 方式接收串口 2 的数据，可以使用以下代码：

#include "stm32f4xx.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_usart.h"
#include "stm32f4xx_dma.h"

#define USART2_DR_ADDRESS    ((uint32_t)0x40004404)

// 接收缓冲区
uint8_t rx_buffer[64];

void USART2_DMA_Config(void)
{
    DMA_InitTypeDef DMA_InitStructure;

    // 使能 DMA1 时钟
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

    // 复位 DMA1 控制器
    DMA_DeInit(DMA1_Stream5);

    // 配置 DMA1 Stream5
    DMA_InitStructure.DMA_Channel = DMA_Channel_4;
    DMA_InitStructure.DMA_PeripheralBaseAddr = USART2_DR_ADDRESS;
    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)rx_buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStructure.DMA_BufferSize = sizeof(rx_buffer);
    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_High;
    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA1_Stream5, &DMA_InitStructure);

    // 使能 DMA1 Stream5
    DMA_Cmd(DMA1_Stream5, ENABLE);  

### 回答2：
以下是基于STM32F407串口2采用DMA方式接收数据的具体代码：

首先，在使用DMA方式接收串口2数据之前，需要初始化串口2和DMA相关的寄存器和配置。

// 初始化串口2
void USART2_Init(void)
{
// 使能串口时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

USART_InitTypeDef USART_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_Init(USART2, &USART_InitStructure);

// 使能串口接收
USART_Cmd(USART2, ENABLE);
}

// 初始化DMA
void DMA_USART2_Rx_Init(void)
{
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

DMA_InitTypeDef DMA_InitStructure;
DMA_InitStructure.DMA_Channel = DMA_Channel_4;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)rx_buffer; // 接收数据缓冲区
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART2->DR;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_BufferSize = BUFFER_SIZE; // 缓冲区大小
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_Init(DMA1_Stream5, &DMA_InitStructure);

// 使能传输完成中断
DMA_ITConfig(DMA1_Stream5, DMA_IT_TC, ENABLE);

// 使能DMA传输
DMA_Cmd(DMA1_Stream5, ENABLE);

// 使能串口接收DMA模式
USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);
}

在main函数中调用上述初始化函数，并实现传输完成中断处理函数。

#define BUFFER_SIZE 256
uint8_t rx_buffer[BUFFER_SIZE];

int main(void)
{
// 初始化系统时钟和相关外设

USART2_Init();
DMA_USART2_Rx_Init();

while (1)
{
// 主程序内容
}
}

// DMA传输完成中断处理函数
void DMA1_Stream5_IRQHandler(void)
{
if (DMA_GetITStatus(DMA1_Stream5, DMA_IT_TCIF5))
{
// 处理接收到的数据
// ...

// 清除DMA传输完成中断标志
DMA_ClearITPendingBit(DMA1_Stream5, DMA_IT_TCIF5);
}
}

以上是基于STM32F407串口2采用DMA方式接收数据的具体代码，代码中的rx_buffer为接收数据的缓冲区，BUFFER_SIZE为缓冲区大小，可根据实际需要进行设置。在DMA传输完成中断处理函数中，可以对接收到的数据进行处理。  

### 回答3：
下面是使用STM32F407的串口2以DMA方式接收数据的具体代码：

#include "stm32f4xx.h"

void DMA_USART2_Configuration(uint8_t *buffer, uint16_t bufferSize)
{
// 使能DMA2的时钟
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);

DMA_InitTypeDef DMA_InitStructure;

// 复位DMA2中的所有寄存器
DMA_DeInit(DMA2_Stream5);

// 配置DMA通道1，数据传输方向为从外设到存储器
DMA_InitStructure.DMA_Channel = DMA_Channel_4;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)buffer;
DMA_InitStructure.DMA_BufferSize = bufferSize;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART2->DR;
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_VeryHigh;
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_Stream5, &DMA_InitStructure);

// 使能DMA2传输完成中断
DMA_ITConfig(DMA2_Stream5, DMA_IT_TC, ENABLE);

// 使能串口2的DMA接收
USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);

// 使能DMA2传输
DMA_Cmd(DMA2_Stream5, ENABLE);
}

int main(void)
{
// 使能串口2和GPIOA的时钟
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

// 配置USART2引脚
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
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);

// 配置USART2的工作模式、波特率等参数
USART_InitTypeDef USART_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(USART2, &USART_InitStructure);

// 配置USART2的中断向量表
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

// 配置USART2的接收DMA
uint8_t receiveBuffer[128];
DMA_USART2_Configuration(receiveBuffer, sizeof(receiveBuffer));

while (1)
{
// 这里继续处理接收到的数据
}
}

// DMA传输完成中断处理函数
void DMA2_Stream5_IRQHandler(void)
{
if (DMA_GetITStatus(DMA2_Stream5, DMA_IT_TCIF5) != RESET)
{
// 清除中断标志位
DMA_ClearITPendingBit(DMA2_Stream5, DMA_IT_TCIF5);

// 处理完接收的数据后，可以进行其他操作
}
}

以上是使用STM32F407的串口2以DMA方式接收数据的代码，其中使用了DMA2的通道5来配置串口2的DMA接收功能，并进行相关的初始化。代码中还提供了一个DMA传输完成中断处理函数，用于处理接收到的数据并进行其他操作。请根据自己的需求对代码进行适当的修改和调整。