STM32串口+DMA使用

? ? ? ? STM32有5個串口資源（USART1，USART2，USART3及UART4，UART5）。其中3個USART（通用同步/異步收/發器universalsynchronous asynchronous receiver and transmitter）；2個UART（通用異步收/發器universalasynchronous receiver and transmitter）；至于USART與UART的區別，如果只是拿來做串口用，沒什么區別，在車載項目里，我們拿來做串口用，USART與UART在編程上并沒有區別。

? ? ? ? 其中USART1，USART2，USART3，UART4支持DMA方式，UART5不支持DMA。(詳見數據手冊stm32f105&107_datesheet_English的P18/2.3.17)。

? ? ? ? DMA（Derect MemoryAcess直接存儲器存取），STM32有2個DMA，DMA1有7個通道，DMA2有5和通道，每個通道對應不同的外設（詳見數據手冊P272/13.3.7）。

1.時鐘RCC配置：串口時鐘 + DMA時鐘 + IO時鐘static void RCC_Configuration(void){RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4,ENABLE); //串口時鐘 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2,ENABLE); //DMA2時鐘 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC| RCC_APB2Periph_AFIO, ENABLE);//IO時鐘} 2.GPIO配置：UART4的TX為PC10腳，發送端配置為復用推挽輸出模式（GPIO_Mode_AF_PP）UART4的RX為PC11腳，接收端配置為浮空輸入模式（GPIO_Mode_IN_FLOATING） static void GPIO_Configuration(void){GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Pin =GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AF_PP; //TX復用推挽輸出模式GPIO_InitStructure.GPIO_Speed =GPIO_Speed_50MHz;GPIO_Init(GPIOC,&GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin =GPIO_Pin_11; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //RX浮空輸入模式GPIO_InitStructure.GPIO_Speed =GPIO_Speed_50MHz;GPIO_Init(GPIOC,&GPIO_InitStructure);}3.中斷NVIC配置：配置兩個DMA通道中斷：UART4的RX的DMA通道為DMA2的通道3；UART4的TX的DMA通道為DMA2的通道5；static void NVIC_Configuration(void){NVIC_InitTypeDef NVIC_InitStructure;NVIC_InitStructure.NVIC_IRQChannel =UART4_IRQn;//串口中斷NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;NVIC_InitStructure.NVIC_IRQChannelSubPriority= 0;NVIC_InitStructure.NVIC_IRQChannelCmd =ENABLE;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel = DMA2_Channel3_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;NVIC_InitStructure.NVIC_IRQChannelCmd =ENABLE;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel = DMA2_Channel5_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd= ENABLE; NVIC_Init(&NVIC_InitStructure);}4.串口配置：即填充串口配置結構體static void UART4_Configuration(void){USART_InitTypeDef USART_InitStructure;USART_InitStructure.USART_BaudRate =115200;USART_InitStructure.USART_WordLength =USART_WordLength_8b;//數據位8位USART_InitStructure.USART_StopBits =USART_StopBits_1;//停止位1位USART_InitStructure.USART_Parity = USART_Parity_No;//無奇偶校驗位USART_InitStructure.USART_HardwareFlowControl= USART_HardwareFlowControl_None;//不采用硬件流控USART_InitStructure.USART_Mode =USART_Mode_Rx | USART_Mode_Tx;//TX、RX都開啟USART_Init(UART4,&USART_InitStructure);USART_Cmd(UART4, ENABLE); //使能UART4外設}5.DMA配置：DMA可以把數據從外設轉移到內存（如串口接收的時候），也可以從內存轉移到外設（如串口發送的時候）；不同方向的數據轉移要各做相應的配置串口接收：void UART4_Start_DMA_Recv(void * recvBuf, uint32_t bufLen){DMA_InitTypeDef DMA_InitStructure;UART4_Configuration();/* DMA1 Channel5 (triggered by USART1 Rxevent) Config */DMA_InitStructure.DMA_PeripheralBaseAddr =(u32)&(UART4->DR);//外設基地址，串口4數據寄存器DMA_InitStructure.DMA_MemoryBaseAddr =(u32)recvBuf;//內存基地址，數組UART4_DMA_HeadBufDMA_InitStructure.DMA_DIR =DMA_DIR_PeripheralSRC;//SRC外設到內存DMA_InitStructure.DMA_BufferSize =bufLen;//DMA數據傳輸長度DMA_InitStructure.DMA_PeripheralInc =DMA_PeripheralInc_Disable;//外設地址不自增DMA_InitStructure.DMA_MemoryInc =DMA_MemoryInc_Enable;//內存地址自增DMA_InitStructure.DMA_PeripheralDataSize =DMA_PeripheralDataSize_Byte;//外設數據單位為1字節DMA_InitStructure.DMA_MemoryDataSize =DMA_MemoryDataSize_Byte;//內存數據單位為1字節DMA_InitStructure.DMA_Mode =DMA_Mode_Normal;//DMA傳輸數據模式，正常模式，傳一輪DMA_InitStructure.DMA_Priority =DMA_Priority_High;//DMA通道優先級DMA_InitStructure.DMA_M2M =DMA_M2M_Disable;//禁止DMA內存到內存傳輸DMA_DeInit(DMA2_Channel3);//UART4的RX為DMA2通道3DMA_Init(DMA2_Channel3,&DMA_InitStructure);DMA_ITConfig(DMA2_Channel3, DMA_IT_TC,ENABLE);//配置DMA2發送完成后產生中斷USART_DMACmd(UART4, USART_DMAReq_Rx,ENABLE);//配置串口向DMA發出Tx請求，請求傳輸數據DMA_Cmd(DMA2_Channel3, ENABLE);//正式開啟DMA}串口發送：void UART4_Start_DMA_Send(void * sendBuf, uint32_t bufLen){DMA_InitTypeDefDMA_InitStructure;if (bufLen == 0)return ;memcpy(UART4_DMA_SendBuf, sendBuf, bufLen);DMA_InitStructure.DMA_PeripheralBaseAddr =(u32)(&UART4->DR);//外設基地址，串口4數據寄存器DMA_InitStructure.DMA_MemoryBaseAddr =(uint32_t)UART4_DMA_SendBuf; DMA_InitStructure.DMA_DIR =DMA_DIR_PeripheralDST;//DST內存到外設 DMA_InitStructure.DMA_BufferSize =bufLen; 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_PeripheralDataSize_Byte; DMA_InitStructure.DMA_Mode =DMA_Mode_Normal; DMA_InitStructure.DMA_Priority =DMA_Priority_High; DMA_InitStructure.DMA_M2M =DMA_M2M_Disable;DMA_DeInit(DMA2_Channel5); //UART4的TX為DMA2通道5DMA_Init(DMA2_Channel5,&DMA_InitStructure); DMA_ITConfig(DMA2_Channel5, DMA_IT_TC,ENABLE);//配置DMA2發送完成后產生中斷USART_DMACmd(UART4,USART_DMAReq_Tx,ENABLE);//配置串口向DMA發出Tx請求，請求傳輸數據DMA_Cmd(DMA2_Channel5, ENABLE);//正式開啟DMAgDMA2Channel5Running = true;}6.DMA中斷函數：串口接收或發送的時候，DMA數據傳輸完成后會產生中斷，在相應中斷函數編寫代碼(注意中斷函數名一定要與啟動文件中斷向量表一致)DMA串口接收完成中斷：void DMA2_Channel3_IRQHandler(void)//接收完成中斷{ OSIntEnter();//ucos進入中斷服務函數if(DMA_GetITStatus(DMA2_IT_TC3)){//獲取剩余長度，一般都為0，調試用DMA_ClearITPendingBit(DMA2_IT_GL3); //清除全部中斷標志 DMA_Cmd(DMA2_Channel3, DISABLE);if(0 == DMAReciveState){if(HOST_MSG_START_CODE_FIRST_BYTE== UART4_DMA_HeadBuf[0])//比較讀取的第1個字節FF{DMAReciveState = 1;UART4_Start_DMA_Recv((void*)(UART4_DMA_HeadBuf + 1), 3);//再讀取后3個字節FFFFFF}else{UART4_Start_DMA_Recv((void*)UART4_DMA_HeadBuf, 1);}}else if(1 == DMAReciveState){if(HOST_MSG_START_CODE ==*(uint32_t *)UART4_DMA_HeadBuf)//比較整個起始碼FFFFFFFF{DMAReciveState = 2;UART4_Start_DMA_Recv((void*)(UART4_DMA_HeadBuf + 4), 8);//再讀取后8個字節（cmdtype+bodylen）}else{DMAReciveState = 0;memset(UART4_DMA_HeadBuf, 0, sizeof(UART4_DMA_HeadBuf));UART4_Start_DMA_Recv((void*)UART4_DMA_HeadBuf, 1);}}else if(2 == DMAReciveState){HOST_MSG_HEADER_T *pMCUMsgHeader;DMAReciveState = 3;pMsgBuffer = (uint8_t*)GetPhoneRecvBuf();//申請一個PhoneRecvBuf接收內存塊if(pMsgBuffer == NULL){DMAReciveState = 0;memset(UART4_DMA_HeadBuf, 0,sizeof(UART4_DMA_HeadBuf));UART4_Start_DMA_Recv((void*)UART4_DMA_HeadBuf, 1);OSIntExit(); //means get out of the inturrept!return;}memcpy(pMsgBuffer,UART4_DMA_HeadBuf, sizeof(HOST_MSG_HEADER_T));//把數組數據（startcode+cmdtype+bodylen）拷貝到內存塊pMCUMsgHeader = (HOST_MSG_HEADER_T*)pMsgBuffer;//指針類型轉換UART4_Start_DMA_Recv((void*)(pMsgBuffer +sizeof(HOST_MSG_HEADER_T)), pMCUMsgHeader->bodyLen + CRC_LEN);//再讀取后面數據（data+crc）到內存塊}else if(3 == DMAReciveState){DMAReciveState = 0;memset(UART4_DMA_HeadBuf, 0,sizeof(UART4_DMA_HeadBuf));UART4_Start_DMA_Recv((void*)UART4_DMA_HeadBuf, 1);//此處再讀1個字節（起始碼第1個字節FF），開始下一輪接收數據if (pMsgBuffer != NULL){PutMsg2PhoneRecvQueue(pMsgBuffer);//把PhoneRecvBuf接收內存塊指針發送到PhoneRecvQ接收消息隊列pMsgBuffer = NULL;}}}OSIntExit();//ucos退出中斷服務函數} DMA串口發送完成中斷：void DMA2_Channel5_IRQHandler(void)//發送完成中斷 {OSIntEnter();if(DMA_GetITStatus(DMA2_IT_TC5)==SET){DMA_ClearFlag(DMA2_IT_GL5);DMA_Cmd(DMA2_Channel5,DISABLE);gDMA2Channel5Running = false;}OSIntExit();}

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DMA常用庫函數：

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文章標簽：?STM32UARTDMA

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