STM32F103 UART4 DMA接收

//网上找了老半天也找不到UART4-DMA的程序，自己调试成功了，特地分享一下

uint8_t UART4_Rx_buffer[512],UART4_Rx_num;
void UART4_Config(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;             
	USART_InitTypeDef USART_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	DMA_InitTypeDef DMA_InitStructure;	 //定义DMA初始化结构体DMA_InitStructure 
	    
//	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0); 	 //选择NVIC优先级分组0  
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);
	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);
 
	//串口4所使用管脚输出输入定义
	
	//定义UART4 Tx (PC.10)脚为复用推挽输出
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;         //IO口的第2脚
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //IO口速度
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;   //IO口复用推挽输出
	GPIO_Init(GPIOC, &GPIO_InitStructure);            //初始化串口1输出IO口
	
	//定义 UART4 Rx (PC.11)为悬空输入 
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;           //IO口的第3脚
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//IO口悬空输入
	GPIO_Init(GPIOC, &GPIO_InitStructure);               //初始化串口1输入IO口
 
	//串口4参数初始化定义部分,串口1参数为9600 ， 8 ，1 ，N  接收中断方式  
	USART_InitStructure.USART_BaudRate = 9600;                  //设定传输速率
	USART_InitStructure.USART_WordLength = USART_WordLength_8b; //设定传输数据位数
	USART_InitStructure.USART_StopBits = USART_StopBits_1;      //设定停止位个数
	USART_InitStructure.USART_Parity = USART_Parity_No ;        //不用校验位
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//不用流量控制
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;                //使用接收和发送功能	
	USART_Init(UART4, &USART_InitStructure);      //初始化串口4
	
	USART_ITConfig(UART4, USART_IT_IDLE,ENABLE);  //使能串口4接收中断	
	USART_Cmd(UART4, ENABLE);                     //使能串口4	
	USART_ClearFlag(UART4, USART_FLAG_TC);        // 清标志(后增加)
 
	DMA_DeInit(DMA2_Channel3);	 //重置DMA 2通道配置	
	DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40004C04;	 //外设地址  
	DMA_InitStructure.DMA_MemoryBaseAddr = (u32)UART4_Rx_buffer;	 //内存地址  
	DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;	 //外设作为数据目的地 
	DMA_InitStructure.DMA_BufferSize = 512;	 //DMA缓存大小:BufferSize 
	DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;	 //外设地址寄存器不递增  
	DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;	  	 //内存地址寄存器递增	
	DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; 	//外设数据宽度为8位 
	DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;	 //内存数据宽度为8位 
	DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;	 //工作在正常缓存模式 
	DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;	 //设置DMA通道优先级为高 
	DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;	 //禁止DMA通道设置为内存至内存传输 
	DMA_Init(DMA2_Channel3, &DMA_InitStructure);	 //初始化
	  
 	DMA_ITConfig(DMA2_Channel3, DMA_IT_TC, ENABLE);
	DMA_ITConfig(DMA2_Channel3, DMA_IT_TE, ENABLE);
 
	USART_DMACmd(UART4, USART_DMAReq_Rx, ENABLE);
	DMA_Cmd(DMA2_Channel3, ENABLE);
	//使能串口4中断
	NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_Init(&NVIC_InitStructure);	
 
	NVIC_InitStructure.NVIC_IRQChannel = DMA2_Channel3_IRQn; 
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; 
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; 
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 
	NVIC_Init(&NVIC_InitStructure);
 }
void UART4_IRQHandler(void)
{
	uint16_t i;
	uint16_t Data_Len;
	if(USART_GetITStatus(UART4, USART_IT_IDLE) != RESET)    //如果为中断
	{  
		DMA_Cmd(DMA2_Channel3, DISABLE);
		Data_Len=512-DMA_GetCurrDataCounter(DMA2_Channel3);
		USART_PutStr(USART1,UART4_Rx_buffer,Data_Len);				
		UART4_Rx_num=0;
		DMA_ClearFlag(DMA2_FLAG_GL3 | DMA2_FLAG_TC3 | DMA2_FLAG_TE3 | DMA2_FLAG_HT3); //清标志
		DMA2_Channel3->CNDTR = 512;                //重装填
		DMA_Cmd(DMA2_Channel3, ENABLE);            //处理完,重开DMA
		//读SR后读DR清除IDLE
		i = UART4->SR;
		i = UART4->DR;
		if(i)			i=0;
		if(Data_Len)	Data_Len=0;   
	}
	if(USART_GetITStatus(UART4, USART_IT_PE | USART_IT_FE | USART_IT_NE) != RESET){    //出错
		USART_ClearITPendingBit(UART4, USART_IT_PE | USART_IT_FE | USART_IT_NE);
	}
	USART_ClearITPendingBit(UART4, USART_IT_TC);
	USART_ClearITPendingBit(UART4, USART_IT_IDLE);	
}
void DMA2_Channel3_IRQHandler(void)
{
	USART_PutStr(USART1," DMA23:rn",9);
	DMA_ClearITPendingBit(DMA2_IT_TC3);
	DMA_ClearITPendingBit(DMA2_IT_TE3);
	DMA_Cmd(DMA2_Channel3, DISABLE);         //关闭DMA,防止处理其间有数据
	DMA2_Channel3->CNDTR = 512;              //重装填
	DMA_Cmd(DMA2_Channel3, ENABLE);          //处理完,重开DMA
}