STM32F407ZET6 USART DMA方式收发数据

串口采用DMA方式收发数据有两种不同的方式，第一种方式：采用DMA传输完成中断进行发送和接收；第二种方式：采用串口总线空闲方式收发数据。这两种方式第二种方式更好一些，因为第二种方式可以收发不定长度的数据帧，然而第一种方式不能。但是第二种方式的逻辑复杂一些，收发过程之前都要判断总线是否是空闲。

在此，以USART2的DMA收发方式举例：

一、使用DMA传输完成中断收发

整体思路：上位机发送四个字节的数据，STM32接收完成后进入DMA中断中，发送下位机STM32定义好的数据给上位机并且清除DMA传输完成中断标志位，最后进入发送完成中断，关闭发送通道，清除DMA发送完成标志位。

在上述思路之前，要进行的自然是串口配置、DMA配置以及中断配置。此处的配置函数如下：

/******************************************
**函数名称：UpperUsart2Init
**函数参数：baudRate 波特率
**函数作用：初始化与上位机通讯的串口Usart2
**硬件引脚：TX--PD5  RX--PD6 
******************************************/
void UpperUsart2Init(int baudRate)
{

	//开启串口时钟、DMA时钟以及相应GPIO时钟
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);  
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE); 
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);  

	GPIO_PinAFConfig(GPIOD,GPIO_PinSource5,GPIO_AF_USART2);
	GPIO_PinAFConfig(GPIOD,GPIO_PinSource6,GPIO_AF_USART2);	
	//PD8(TX)设置成复用推挽输出
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //| GPIO_Pin_9;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
	GPIO_Init(GPIOD, &GPIO_InitStructure);
	//PD9(RX)设置成浮空输入
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
	GPIO_Init(GPIOD, &GPIO_InitStructure); 	
	
	// USART2_DMA_RX DMA1_Stream5 DMA_Channel_4 
  	DMA_DeInit(DMA1_Stream5);
  	DMA_InitStructure.DMA_Channel = DMA_Channel_4;
  	DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART2->DR);
  	DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&upperRxBuffer;
  	DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  	DMA_InitStructure.DMA_BufferSize = UPPERRBSIZE;
  	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;//如果是Normal只能接受一次，故采用循环模式
 	DMA_InitStructure.DMA_Priority = DMA_Priority_High;
 	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(DMA1_Stream5, &DMA_InitStructure);
	
	// USART2_DMA_TX DMA1_Stream6 DMA_Channel_4 
	DMA_DeInit(DMA1_Stream6);
  	DMA_InitStructure.DMA_Channel = DMA_Channel_4;
	DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) &(USART2->DR);
	DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&upperTxBuffer;
	DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
	DMA_InitStructure.DMA_BufferSize = UPPERTBSIZE;
	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_Mode_Circular;
	DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  	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(DMA1_Stream6, &DMA_InitStructure);

	//USART2设置 115200 8 1 0 NONE
	USART_InitStructure.USART_BaudRate = baudRate;
	USART_InitStructure.USART_WordLength = USART_WordLength_8b;
	USART_InitStructure.USART_StopBits = USART_StopBits_1;
	USART_InitStructure.USART_Parity = USART_Parity_No ;
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
	USART_Init(USART2,&USART_InitStructure);
	
	// Configure one bit for preemption priority 
  	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
  	// Enable DMA1_Stream5 Interrupt 
  	NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream5_IRQn;
 	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 4;
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  	NVIC_Init(&NVIC_InitStructure);
  	// Enable DMA1_Stream6 Interrupt 
  	NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream6_IRQn;
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  	NVIC_Init(&NVIC_InitStructure);
  	// Enable USART2 Interrupt 
  	NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 5;
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  	NVIC_Init(&NVIC_InitStructure);	
	
	//开启串口、DMA和串口总线空闲中断
	DMA_Cmd(DMA1_Stream5,ENABLE);
	DMA_Cmd(DMA1_Stream6,DISABLE);
	USART_DMACmd(USART2,USART_DMAReq_Tx,ENABLE);
	USART_DMACmd(USART2,USART_DMAReq_Rx,ENABLE);  
	DMA_ITConfig(DMA1_Stream5, DMA_IT_TC, ENABLE);
	DMA_ITConfig(DMA1_Stream6, DMA_IT_TC, ENABLE);
	DMA_ClearITPendingBit(DMA1_Stream5, DMA_IT_TCIF5); //标志位设置为默认值
	DMA_ClearITPendingBit(DMA1_Stream6, DMA_IT_TCIF6);  	
	USART_ITConfig(USART2,USART_IT_IDLE,ENABLE); 
//	USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
	USART_Cmd(USART2, ENABLE);	
}

上述程序段功能是配置串口、DMA以及相应中断。（一定要注意开启时钟）

在本程序中STM32发送给上位机的数据为uint8_t data[4] = {0x01,0x03,0x04,0x06};

下面这个中断是DMA接收完成中断，完成功能是：清除接收完成标志位，并且向上位机发送预定义数据。

/******************************************
**函数名称：DMA1_Stream5_IRQHandler
**函数参数：无
**函数作用：串口2 DMA接受完成时发送数据给上位机
******************************************/
void DMA1_Stream5_IRQHandler(void)
{
	if(SET ==  DMA_GetITStatus(DMA1_Stream5, DMA_IT_TCIF5))
	{ 
		DMA_Cmd(DMA1_Stream5,DISABLE);
		DMA_ClearFlag(DMA1_Stream5,DMA_FLAG_TCIF5);
		DMA_Cmd(DMA1_Stream5,ENABLE);	
		
		DMA_SetCurrDataCounter(DMA1_Stream6,UPPERTBSIZE); 
		memcpy(upperTxBuffer,data,UPPERTBSIZE);		
		DMA_Cmd(DMA1_Stream6,ENABLE);		
	}
}

下面这个中断是DMA传输完成中断，完成功能是：清除发送完成标志位。

/******************************************
**函数名称：DMA1_Stream6_IRQHandler
**函数参数：无
**函数作用：串口2发送完成时中断入口函数，关闭传输通道并且清除标志
******************************************/
void DMA1_Stream6_IRQHandler(void) //UART2_TX
{
	if(SET == DMA_GetITStatus(DMA1_Stream6,DMA_IT_TCIF6))
	{
		DMA_Cmd(DMA1_Stream6,DISABLE);
		DMA_ClearFlag(DMA1_Stream6, DMA_FLAG_TCIF6);
	}
}

资源下载地址：http://download.csdn.net/download/fsniper/9773300