STM32F4 UART1 DMA發送和接收不定長度數據

STM32F4 串口收發使用DMA還是很方便的。但是配置DMA時需要配置數據長度，這一點對於發送來說可以預估計自己發送的長度來配置DMA發送數據長度，但是對於接收不是很好解決，因爲如果使用DMA接收中斷是要配置的數據長度減到0才能出發中斷。但是我們無法判斷接受數據的長度，導致無法判斷數據接收完成。網上有提出的解決方法是用定時器固定週期的讀DMA接收的長度來判斷是否接收完成，也有使用UART的空閒中斷來處理的。在這裏我使用UART的空閒中斷來處理接收不定長數據。當然也要打開DMA接收完成中斷，處理數據接收超過DMA配置的長度導致的DMA接收中斷。

1.使用DMA發送時每次發送數據前需要配置發送的數據長度，此時要注意應先關閉DMA，然後配置數據長度，最後開啓DMA發送，同時在DMA發送中斷裏面不要忘記清除相應的中斷標誌位。

2.DMA接收長度達到配置長度後會導致接收中斷，此時在中斷處理函數內要先關閉DMA，然後讀出數據長度，清掉相應的中斷標誌位，最後重新配置DMA接收長度並打開DMA接收。在這裏的DMA中斷指示爲了防護一次性接收數據超過DMA配置長度。

3.UART空閒中斷，利用空閒中斷可以很好地判斷DMA接收不定長度的數據是否完成。初始化UART時打開空閒中斷。當數據接收完成後會觸發UART空閒中斷。在中斷內首先關閉DMA，讀出DMA接收到的數據長度，清除DMA標誌，重新配置DMA接收長度，清除空閒中斷標誌IDLE。這裏要注意清除IDLE要由軟件序列清除即依次讀取USART1->SR;和USART1->DR;

下面貼出代碼方便以後查看

u8  ReceiveBuff[RECEIVE_BUF_SIZE];   //接收緩衝
u8  SendBuff[SEND_BUF_SIZE];	//發送數據緩衝區

u16 UART1_ReceiveSize = 0;

//初始化IO 串口1 
//bound:波特率
void uart_init(u32 bound)
{
	//GPIO端口設置
	GPIO_InitTypeDef GPIO_InitStructure;
	USART_InitTypeDef USART_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	DMA_InitTypeDef  DMA_InitStructure;

	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //使能GPIOA時鐘
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);//使能USART1時鐘
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2,ENABLE);//DMA2時鐘使能 

	//串口1對應引腳複用映射
	GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1); //GPIOA9複用爲USART1
	GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1); //GPIOA10複用爲USART1

	//USART1端口配置
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10; //GPIOA9與GPIOA10
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//複用功能
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;	//速度50MHz
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推輓複用輸出
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
	GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA9，PA10

	//USART1 初始化設置
	USART_InitStructure.USART_BaudRate = bound;//波特率設置
	USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字長爲8位數據格式
	USART_InitStructure.USART_StopBits = USART_StopBits_1;//一個停止位
	USART_InitStructure.USART_Parity = USART_Parity_No;//無奇偶校驗位
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//無硬件數據流控制
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;	//收發模式
	USART_Init(USART1, &USART_InitStructure); //初始化串口1

	USART_Cmd(USART1, ENABLE);  //使能串口1 

	//USART_ClearFlag(USART1, USART_FLAG_TC);
	
	USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);//開啓相關中斷

	//Usart1 NVIC 配置
	NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;//串口1中斷通道
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;//搶佔優先級3
	NVIC_InitStructure.NVIC_IRQChannelSubPriority =3;		//子優先級3
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			//IRQ通道使能
	NVIC_Init(&NVIC_InitStructure);	//根據指定的參數初始化VIC寄存器、

	USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);  //使能串口1的DMA發送   
	USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);  //使能串口1的DMA接收


	//****************************配置UART1發送
	DMA_DeInit(DMA2_Stream7);
	while (DMA_GetCmdStatus(DMA2_Stream7) != DISABLE);//等待DMA可配置 
	/* 配置 DMA Stream */
	DMA_InitStructure.DMA_Channel = DMA_Channel_4;  //通道選擇
	DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;//DMA外設地址
	DMA_InitStructure.DMA_Memory0BaseAddr = (u32)SendBuff;//DMA 存儲器0地址
	DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;//存儲器到外設模式
	DMA_InitStructure.DMA_BufferSize = SEND_BUF_SIZE;//數據傳輸量 
	DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外設非增量模式
	DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存儲器增量模式
	DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外設數據長度:8位
	DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//存儲器數據長度:8位
	DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 
	DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等優先級
	DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         
	DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
	DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//存儲器突發單次傳輸
	DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;//外設突發單次傳輸
	DMA_Init(DMA2_Stream7, &DMA_InitStructure);//初始化DMA Stream
	//DMA NVIC  
	NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream7_IRQn;  
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  
	NVIC_Init(&NVIC_InitStructure);  
	DMA_ITConfig(DMA2_Stream7,DMA_IT_TC,ENABLE);

	//****************************配置UART1接收
	DMA_DeInit(DMA2_Stream5);
	while (DMA_GetCmdStatus(DMA2_Stream5) != DISABLE);//等待DMA可配置 
	/* 配置 DMA Stream */
	DMA_InitStructure.DMA_Channel = DMA_Channel_4;  //通道選擇
	DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;//DMA外設地址
	DMA_InitStructure.DMA_Memory0BaseAddr = (u32)ReceiveBuff;//DMA 存儲器0地址
	DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory ;//外設到存儲器模式
	DMA_InitStructure.DMA_BufferSize = RECEIVE_BUF_SIZE;//數據傳輸量 
	DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外設非增量模式
	DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存儲器增量模式
	DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外設數據長度:8位
	DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//存儲器數據長度:8位
	DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 
	DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等優先級
	DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         
	DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
	DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//存儲器突發單次傳輸
	DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;//外設突發單次傳輸
	DMA_Init(DMA2_Stream5, &DMA_InitStructure);//初始化DMA Stream
	//DMA NVIC  
	NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream5_IRQn;  
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;  
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  
	NVIC_Init(&NVIC_InitStructure);  
	DMA_Cmd(DMA2_Stream5, ENABLE);  //開啓DMA傳輸 
	
	DMA_ITConfig(DMA2_Stream5,DMA_IT_TC,ENABLE);
	
}

//開啓一次DMA傳輸
//DMA_Streamx:DMA數據流,DMA1_Stream0~7/DMA2_Stream0~7 
//ndtr:數據傳輸量  
void DmaSendDataProc(DMA_Stream_TypeDef *DMA_Streamx,u16 ndtr)
{
 
	DMA_Cmd(DMA_Streamx, DISABLE);                      //關閉DMA傳輸 
	
	while (DMA_GetCmdStatus(DMA_Streamx) != DISABLE){}	//確保DMA可以被設置  
		
	DMA_SetCurrDataCounter(DMA_Streamx,ndtr);          //數據傳輸量  
 
	DMA_Cmd(DMA_Streamx, ENABLE);                      //開啓DMA傳輸 
}	  

///////////////////////////////////////////////////////////////////////////
//串口1
//發送單字節
 void SendByteInfoProc(u8 nSendInfo)
{
	u8 *pBuf = NULL;
	//指向發送緩衝區
	pBuf = SendBuff;
	*pBuf++ = nSendInfo;

	DmaSendDataProc(DMA2_Stream7,1); //開始一次DMA傳輸！	  
}
//發送多字節
void SendBytesInfoProc(u8* pSendInfo, u16 nSendCount)
{
	u16 i = 0;
	u8 *pBuf = NULL;
	//指向發送緩衝區
	pBuf = SendBuff;

	for (i=0; i<nSendCount; i++)
	{
		*pBuf++ = pSendInfo[i];
	}
	//DMA發送方式
	DmaSendDataProc(DMA2_Stream7,nSendCount); //開始一次DMA傳輸！	  
}

//發送完成中斷
void DMA2_Stream7_IRQHandler(void)
{
	//清除標誌
	if(DMA_GetFlagStatus(DMA2_Stream7,DMA_FLAG_TCIF7)!=RESET)//等待DMA2_Steam7傳輸完成
	{ 
		DMA_ClearFlag(DMA2_Stream7,DMA_FLAG_TCIF7);//清除DMA2_Steam7傳輸完成標誌
	}
}
//接收完成中斷
void DMA2_Stream5_IRQHandler(void)
{
	//清除標誌
	if(DMA_GetFlagStatus(DMA2_Stream5,DMA_FLAG_TCIF5)!=RESET)//等待DMA2_Steam7傳輸完成
	{ 
		DMA_Cmd(DMA2_Stream5, DISABLE); //關閉DMA,防止處理其間有數據

		UART1_ReceiveSize =RECEIVE_BUF_SIZE - DMA_GetCurrDataCounter(DMA2_Stream5);
		if(UART1_ReceiveSize !=0)
		{
			OSSemPost(DMAReceiveSize_Sem);
		}
		
		DMA_ClearFlag(DMA2_Stream5,DMA_FLAG_TCIF5 | DMA_FLAG_FEIF5 | DMA_FLAG_DMEIF5 | DMA_FLAG_TEIF5 | DMA_FLAG_HTIF5);//清除DMA2_Steam7傳輸完成標誌
		DMA_SetCurrDataCounter(DMA2_Stream5, RECEIVE_BUF_SIZE);
		DMA_Cmd(DMA2_Stream5, ENABLE);     //打開DMA,
	}
}

//空閒中斷
void USART1_IRQHandler(void)
{
	u16 data;
	if(USART_GetITStatus(USART1,USART_IT_IDLE) != RESET)
	{
		DMA_Cmd(DMA2_Stream5, DISABLE); //關閉DMA,防止處理其間有數據

		data = USART1->SR;
		data = USART1->DR;
		
		UART1_ReceiveSize =RECEIVE_BUF_SIZE - DMA_GetCurrDataCounter(DMA2_Stream5);
		if(UART1_ReceiveSize !=0)
		{
			OSSemPost(DMAReceiveSize_Sem);
		}
		DMA_ClearFlag(DMA2_Stream5,DMA_FLAG_TCIF5 | DMA_FLAG_FEIF5 | DMA_FLAG_DMEIF5 | DMA_FLAG_TEIF5 | DMA_FLAG_HTIF5);//清除DMA2_Steam7傳輸完成標誌
		DMA_SetCurrDataCounter(DMA2_Stream5, RECEIVE_BUF_SIZE);
		DMA_Cmd(DMA2_Stream5, ENABLE);     //打開DMA,

	}
} 

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