STM32F103的串口2的DMA接收发送

不废话上程序

第一步变量设置:

unsigned char rx2_data[256]={0};        //接收缓存区

unsigned char tx2_data[256]={0};        //发松缓存区

unsigned char rx2_n=0;                   //接收字节个数

unsigned char flag_usart2=0;		//帧接收完成标志

第二步:USART2串口设置 

//USART2 通信设置，
//PA2------------TX2
//PA3------------RX2
 void init_usart2(u32 bound)
{
	GPIO_InitTypeDef 	GPIO_InitStructure;
	USART_InitTypeDef 	USART_InitStructure;
	NVIC_InitTypeDef 	NVIC_InitStructure;
	
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
	USART_DeInit(USART2);  							//复位串口2
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;		//PA.2--TX
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
 
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;		//PA.3--RX
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	USART_InitStructure.USART_BaudRate = bound;        //波特率
	USART_InitStructure.USART_WordLength = USART_WordLength_9b;    //带一位校验位
	USART_InitStructure.USART_StopBits = USART_StopBits_1;        //一位停止位
	USART_InitStructure.USART_Parity = USART_Parity_Even;        //偶校验
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;	//无硬件流控制
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
	USART_Init(USART2, &USART_InitStructure);
	
//	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;        //接收中断
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7;	//主优先级---抢占优先级,优先级数字越小，优先级越高
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;			//次优先级---响应优先级
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;				
	NVIC_Init(&NVIC_InitStructure);
	
//使能串口接收中断修改为串口总线空闲中断	
//	USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);		//设置接收字节中断
	USART_ITConfig(USART2,USART_IT_IDLE, ENABLE);		//设置接收帧中断（串口空闲中断）
	USART_Cmd(USART2, ENABLE);
} 

第三DMA设置

USART2_TX----PA2------DMA1通道7,RAM--->>USART2
USART2_RX----PA3------DMA1通道6,USART2--->>RAM
void DMA1_USART2_Init(void)
{
	DMA_InitTypeDef     DMA1_Init;
	NVIC_InitTypeDef    NVIC_InitStructure;
	
	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);						//使能DMA1时钟

	///DMA_USART2_RX  USART2->RAM的数据传输
	DMA_DeInit(DMA1_Channel6);									//将DMA的通道6寄存器重设为缺省值 
	DMA1_Init.DMA_PeripheralBaseAddr = (u32)(&USART2->DR);		//启动传输前装入实际RAM地址
	DMA1_Init.DMA_MemoryBaseAddr = (u32)rx2_data;            	//设置接收缓冲区首地址
	DMA1_Init.DMA_DIR = DMA_DIR_PeripheralSRC;					//数据传输方向，从外设读取到内存
	DMA1_Init.DMA_BufferSize = 256;							//DMA通道的DMA缓存的大小
	DMA1_Init.DMA_PeripheralInc = DMA_PeripheralInc_Disable;			//外设地址寄存器不变
	DMA1_Init.DMA_MemoryInc = DMA_MemoryInc_Enable;						//内存地址寄存器递增
	DMA1_Init.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;		//数据宽度为8位
	DMA1_Init.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;				//数据宽度为8位
	DMA1_Init.DMA_Mode = DMA_Mode_Normal;								//工作在正常模式
	DMA1_Init.DMA_Priority = DMA_Priority_High; 				//DMA通道 x拥有高优先级 
	DMA1_Init.DMA_M2M = DMA_M2M_Disable;						//DMA通道x没有设置为内存到内存传输
	 
	DMA_Init(DMA1_Channel6,&DMA1_Init); 							//对DMA通道6进行初始化
	
//DMA_USART2_TX  RAM->USART2的数据传输//
	DMA_DeInit(DMA1_Channel7);								//将DMA的通道7寄存器重设为缺省值 
	DMA1_Init.DMA_PeripheralBaseAddr = (u32)(&USART2->DR);	//启动传输前装入实际RAM地址
	DMA1_Init.DMA_MemoryBaseAddr = (u32)tx2_data;       //设置发送缓冲区首地址
	DMA1_Init.DMA_DIR = DMA_DIR_PeripheralDST; 			//数据传输方向，从内存发送到外设
	DMA1_Init.DMA_BufferSize = 256;				//DMA通道的DMA缓存的大小
	DMA1_Init.DMA_PeripheralInc = DMA_PeripheralInc_Disable;		//外设地址寄存器不变
	DMA1_Init.DMA_MemoryInc = DMA_MemoryInc_Enable;			//内存地址寄存器递增
	DMA1_Init.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;	//数据宽度为8位
	DMA1_Init.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;		//数据宽度为8位
	DMA1_Init.DMA_Mode = DMA_Mode_Normal;					//工作在正常模式
	DMA1_Init.DMA_Priority = DMA_Priority_High; 			//DMA通道 x拥有高优先级 
	DMA1_Init.DMA_M2M = DMA_M2M_Disable;					//DMA通道x没有设置为内存到内存传输

	DMA_Init(DMA1_Channel7,&DMA1_Init); 						//对DMA通道7进行初始化
	
	//DMA1通道6 NVIC 配置
	NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel6_IRQn;				//NVIC通道设置
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7 ;				//抢占优先级
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;						//子优先级
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;							//IRQ通道使能
	NVIC_Init(&NVIC_InitStructure);											//根据指定的参数初始化NVIC寄存器
 
	//DMA1通道7 NVIC 配置
	NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel7_IRQn;				//NVIC通道设置
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7 ;				//抢占优先级
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;						//子优先级
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;						//IRQ通道使能
	NVIC_Init(&NVIC_InitStructure);									//根据指定的参数初始化NVIC寄存器

	DMA_ITConfig(DMA1_Channel6,DMA_IT_TC,ENABLE);				//开USART2 Rx DMA中断
	DMA_ITConfig(DMA1_Channel7,DMA_IT_TC,ENABLE);				//开USART2 Tx DMA中断

	DMA_Cmd(DMA1_Channel6,ENABLE);           					//使DMA通道6开启工作
	DMA_Cmd(DMA1_Channel7,DISABLE);           					//使DMA通道7停止工作
	 
	USART_DMACmd(USART2, USART_DMAReq_Tx, ENABLE);        		//开启串口DMA发送
	USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);        		//开启串口DMA接收
}

第四步中断设置

//DMA1通道7中断,发送完成
void DMA1_Channel7_IRQHandler(void)
{
	if(DMA_GetITStatus(DMA1_IT_TC7)!= RESET)	//DMA发送完成标志//传输完成中断
	{
		DMA_ClearITPendingBit(DMA1_IT_TC7); 	//清除中断标志 
		DMA_Cmd(DMA1_Channel7, DISABLE );   	//关闭USART2 TX DMA1 的通道//关闭数据输出通道
	}
}

接收完成,空闲中断
USART2_RX----PA3------DMA1通道6,USART2--->>RAM
void USART2_IRQHandler(void)                	
{										//接收数据长度
	u8	clear;
	clear=clear;
	if(USART_GetITStatus(USART2, USART_IT_IDLE) != RESET)			//串口2空闲中断
	{
	清除串口2空闲中断IDLE标志位
		clear = USART2->SR;  //串口状态寄存器
		clear = USART2->DR; // 串口数据寄存器 

		USART_ClearFlag(USART2,USART_FLAG_TC);					//清除USART2标志位
		DMA_Cmd(DMA1_Channel6, DISABLE );   //关闭USART2 TX DMA1 所指示的通道
		rx2_n = 256 - DMA1_Channel6->CNDTR;	//获得接收到的字节数
		flag_usart2=1;					//DMA收到数据标识
		DMA1_Channel6->CNDTR = 256;			//设定DMA通道的DMA缓存的大小
		DMA_Cmd(DMA1_Channel6, ENABLE);     //使能USART2 TX DMA1 所指示的通道	
  }
}

 第五步发送数据:

//DMA 发送数据
void dam_send(u8	*p, u8	len)
{
	DMA_Cmd(DMA1_Channel7, DISABLE);				//关闭DMA发送
	memcpy(tx2_data,p,len);        //#include	<string.h>	
	DMA_SetCurrDataCounter(DMA1_Channel7,len);//设置要发送的字节个数
	DMA_Cmd(DMA1_Channel7, ENABLE);				//开始DMA发送
}