STM32F4 UART DMA初始化

转载于http://m.blog.csdn.net/louyangyang91/article/details/51504559

F4的片子内部DMA初始化和F103的有很大区别，在这里引入了数据流（Stream），2个DMA共16的数据流（每个控制器8个），每个数据流则可已处理多达8个通道的数据，每个通道都有一个仲裁器处理DMA请求的优先级。下面贴出DMA请求映射事例

在DMA2中可以看出UART1的发送是数据流7的第4通道，接收是数据流5的第4通道。所以在配置DMA时要注意选择对应的数据流然后配置对应的通道，最后初始化对应数据流和对应的通道。

下面贴出代码

//****************************配置UART1 DMA发送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;  //通道选择DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;//DMA外设地址DMA_InitStructure.DMA_Memory0BaseAddr = (u32)SendBuff;//DMA 存储器0地址DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;//存储器到外设模式DMA_InitStructure.DMA_BufferSize = SEND_BUF_SIZE;//数据传输量 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设非增量模式DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存储器增量模式DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外设数据长度:8位DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//存储器数据长度:8位DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等优先级DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//存储器突发单次传输DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;//外设突发单次传输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 DMA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;  //通道选择DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;//DMA外设地址DMA_InitStructure.DMA_Memory0BaseAddr = (u32)ReceiveBuff;//DMA 存储器0地址DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory ;//外设到存储器模式DMA_InitStructure.DMA_BufferSize = RECEIVE_BUF_SIZE;//数据传输量 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设非增量模式DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存储器增量模式DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外设数据长度:8位DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//存储器数据长度:8位DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;// 使用普通模式 DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//中等优先级DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//存储器突发单次传输DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;//外设突发单次传输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);  //开启DMA传输 DMA_ITConfig(DMA2_Stream5,DMA_IT_TC,ENABLE);