STM32F4 UART1 DMA發送和接收不定長度資料

標籤：

STM32F4 串口收發使用DMA還是很方便的。但是配置DMA時需要配置資料長度，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發送資料長度，但是對於接收不是很好解決，因為如果使用DMA接收中斷是要配置的資料長度減到0才能出發中斷。但是我們無法判斷接受資料的長度，導致無法判斷資料接收完成。網上有提出的解決方案是用定時器固定周期的讀DMA接收的長度來判斷是否接收完成，也有使用UART的空閑中斷來處理的。在這裡我使用UART的空閑中斷來處理接收不定長資料。當然也要開啟DMA接收完成中斷，處理資料接收超過DMA配置的長度導致的DMA接收中斷。

1.使用DMA發送時每次發送資料前需要配置發送的資料長度，此時要注意應先關閉DMA，然後配置資料長度，最後開啟DMA發送，同時在DMA發送中斷裡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，然後讀出資料長度，清掉相應的中斷標誌位，最後重新設定DMA接收長度並開啟DMA接收。在這裡的DMA中斷指示為了防護一次性接收資料超過DMA配置長度。

3.UART空閑中斷，利用空閑中斷可以很好地判斷DMA接收不定長度的資料是否完成。初始化UART時開啟空閑中斷。當資料接收完成後會觸發UART空閑中斷。在中斷內首先關閉DMA，讀出DMA接收到的資料長度，清除DMA標誌，重新設定DMA接收長度，清除空閑中斷標誌IDLE。這裡要注意清除IDLE要由軟體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];//發送資料緩衝區u16 UART1_ReceiveSize = 0;//初始化IO 串口1 //bound:傳輸速率void uart_init(u32 bound){//GPIO連接埠設定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複用為USART1GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1); //GPIOA10複用為USART1//USART1連接埠配置GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10; //GPIOA9與GPIOA10GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//複用功能GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//速度50MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽複用輸出GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA9，PA10//USART1 初始化設定USART_InitStructure.USART_BaudRate = bound;//傳輸速率設定USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字長為8位元據格式USART_InitStructure.USART_StopBits = USART_StopBits_1;//一個停止位USART_InitStructure.USART_Parity = USART_Parity_No;//無同位位元USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//無硬體資料流控制USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//收發模式USART_Init(USART1, &USART_InitStructure); //初始化串口1USART_Cmd(USART1, ENABLE);  //使能串口1 //USART_ClearFlag(USART1, USART_FLAG_TC);USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);//開啟相關中斷//Usart1 NVIC 配置NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;//串口1中斷通道NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;//搶佔優先順序3NVIC_InitStructure.NVIC_IRQChannelSubPriority =3;//子優先順序3NVIC_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 儲存空間0地址DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;//儲存空間到外設模式DMA_InitStructure.DMA_BufferSize = SEND_BUF_SIZE;//資料轉送量 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外設非增量模式DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//儲存空間增量模式DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外設資料長度:8位DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//儲存空間資料長度:8位DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等優先順序DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//儲存空間突發單次傳輸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 儲存空間0地址DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory ;//外設到儲存空間模式DMA_InitStructure.DMA_BufferSize = RECEIVE_BUF_SIZE;//資料轉送量 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外設非增量模式DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//儲存空間增量模式DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外設資料長度:8位DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//儲存空間資料長度:8位DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等優先順序DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//儲存空間突發單次傳輸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);  //開啟DMA傳輸 DMA_ITConfig(DMA2_Stream5,DMA_IT_TC,ENABLE);}//開啟一次DMA傳輸//DMA_Streamx:DMA資料流,DMA1_Stream0~7/DMA2_Stream0~7 //ndtr:資料轉送量  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可以被設定  DMA_SetCurrDataCounter(DMA_Streamx,ndtr);          //資料轉送量   DMA_Cmd(DMA_Streamx, ENABLE);                      //開啟DMA傳輸 }  /////////////////////////////////////////////////////////////////////////////串口1//發送單位元組 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！  }//發送多位元組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,防止處理其間有資料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);     //開啟DMA,}}//空閑中斷void USART1_IRQHandler(void){u16 data;if(USART_GetITStatus(USART1,USART_IT_IDLE) != RESET){DMA_Cmd(DMA2_Stream5, DISABLE); //關閉DMA,防止處理其間有資料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);     //開啟DMA,}} 

STM32F4 UART1 DMA發送和接收不定長度資料