STM32F4 UART1 DMA发送和接收不定长度数据
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转载于http://blog.csdn.net/louyangyang91/article/details/51504177
STM32F4 串口收发使用DMA还是很方便的。但是配置DMA时需要配置数据长度,这一点对于发送来说可以预估计自己发送的长度来配置DMA发送数据长度,但是对于接收不是很好解决,因为如果使用DMA接收中断是要配置的数据长度减到0才能出发中断。但是我们无法判断接受数据的长度,导致无法判断数据接收完成。网上有提出的解决方法是用定时器固定周期的读DMA接收的长度来判断是否接收完成,也有使用UART的空闲中断来处理的。在这里我使用UART的空闲中断来处理接收不定长数据。当然也要打开DMA接收完成中断,处理数据接收超过DMA配置的长度导致的DMA接收中断。
1.使用DMA发送时每次发送数据前需要配置发送的数据长度,此时要注意应先关闭DMA,然后配置数据长度,最后开启DMA发送,同时在DMA发送中断里面不要忘记清除相应的中断标志位。
2.DMA接收长度达到配置长度后会导致接收中断,此时在中断处理函数内要先关闭DMA,然后读出数据长度,清掉相应的中断标志位,最后重新配置DMA接收长度并打开DMA接收。在这里的DMA中断指示为了防护一次性接收数据超过DMA配置长度。
3.UART空闲中断,利用空闲中断可以很好地判断DMA接收不定长度的数据是否完成。初始化UART时打开空闲中断。当数据接收完成后会触发UART空闲中断。在中断内首先关闭DMA,读出DMA接收到的数据长度,清除DMA标志,重新配置DMA接收长度,清除空闲中断标志IDLE。这里要注意清除IDLE要由软件序列清除即依次读取USART1->SR;和USART1->DR;
下面贴出代码方便以后查看
- u8 ReceiveBuff[RECEIVE_BUF_SIZE];
- u8 SendBuff[SEND_BUF_SIZE];
-
- u16 UART1_ReceiveSize = 0;
-
-
-
- void uart_init(u32 bound)
- {
-
- GPIO_InitTypeDef GPIO_InitStructure;
- USART_InitTypeDef USART_InitStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- DMA_InitTypeDef DMA_InitStructure;
-
- RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
- RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2,ENABLE);
-
-
- GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
- GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
-
-
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
- GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
- GPIO_Init(GPIOA,&GPIO_InitStructure);
-
-
- USART_InitStructure.USART_BaudRate = bound;
- USART_InitStructure.USART_WordLength = USART_WordLength_8b;
- USART_InitStructure.USART_StopBits = USART_StopBits_1;
- USART_InitStructure.USART_Parity = USART_Parity_No;
- USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
- USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
- USART_Init(USART1, &USART_InitStructure);
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- USART_Cmd(USART1, ENABLE);
-
-
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- USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);
-
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- NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;
- NVIC_InitStructure.NVIC_IRQChannelSubPriority =3;
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
- NVIC_Init(&NVIC_InitStructure);
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- USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);
- USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
-
-
-
- DMA_DeInit(DMA2_Stream7);
- while (DMA_GetCmdStatus(DMA2_Stream7) != DISABLE);
- /* 配置 DMA Stream */
- DMA_InitStructure.DMA_Channel = DMA_Channel_4;
- DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;
- DMA_InitStructure.DMA_Memory0BaseAddr = (u32)SendBuff;
- DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
- DMA_InitStructure.DMA_BufferSize = SEND_BUF_SIZE;
- 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_MemoryDataSize_Byte;
- DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
- DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
- DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
- DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
- DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
- DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
- DMA_Init(DMA2_Stream7, &DMA_InitStructure);
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- 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);
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-
- DMA_DeInit(DMA2_Stream5);
- while (DMA_GetCmdStatus(DMA2_Stream5) != DISABLE);
- /* 配置 DMA Stream */
- DMA_InitStructure.DMA_Channel = DMA_Channel_4;
- DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART1->DR;
- DMA_InitStructure.DMA_Memory0BaseAddr = (u32)ReceiveBuff;
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory ;
- DMA_InitStructure.DMA_BufferSize = RECEIVE_BUF_SIZE;
- 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_MemoryDataSize_Byte;
- DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
- DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
- DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
- DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
- DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
- DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
- DMA_Init(DMA2_Stream5, &DMA_InitStructure);
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- 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);
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- DMA_ITConfig(DMA2_Stream5,DMA_IT_TC,ENABLE);
-
- }
-
-
-
-
- void DmaSendDataProc(DMA_Stream_TypeDef *DMA_Streamx,u16 ndtr)
- {
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- DMA_Cmd(DMA_Streamx, DISABLE);
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- while (DMA_GetCmdStatus(DMA_Streamx) != DISABLE){}
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- DMA_SetCurrDataCounter(DMA_Streamx,ndtr);
-
- DMA_Cmd(DMA_Streamx, ENABLE);
- }
-
-
-
-
- void SendByteInfoProc(u8 nSendInfo)
- {
- u8 *pBuf = NULL;
-
- pBuf = SendBuff;
- *pBuf++ = nSendInfo;
-
- DmaSendDataProc(DMA2_Stream7,1);
- }
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- void SendBytesInfoProc(u8* pSendInfo, u16 nSendCount)
- {
- u16 i = 0;
- u8 *pBuf = NULL;
-
- pBuf = SendBuff;
-
- for (i=0; i<nSendCount; i++)
- {
- *pBuf++ = pSendInfo[i];
- }
-
- DmaSendDataProc(DMA2_Stream7,nSendCount);
- }
-
-
- void DMA2_Stream7_IRQHandler(void)
- {
-
- if(DMA_GetFlagStatus(DMA2_Stream7,DMA_FLAG_TCIF7)!=RESET)
- {
- DMA_ClearFlag(DMA2_Stream7,DMA_FLAG_TCIF7);
- }
- }
-
- void DMA2_Stream5_IRQHandler(void)
- {
-
- if(DMA_GetFlagStatus(DMA2_Stream5,DMA_FLAG_TCIF5)!=RESET)
- {
- DMA_Cmd(DMA2_Stream5, DISABLE);
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- 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);
- DMA_SetCurrDataCounter(DMA2_Stream5, RECEIVE_BUF_SIZE);
- DMA_Cmd(DMA2_Stream5, ENABLE);
- }
- }
-
-
- void USART1_IRQHandler(void)
- {
- u16 data;
- if(USART_GetITStatus(USART1,USART_IT_IDLE) != RESET)
- {
- DMA_Cmd(DMA2_Stream5, DISABLE);
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- data = USART1->SR;
- data = USART1->DR;
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- 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);
- DMA_SetCurrDataCounter(DMA2_Stream5, RECEIVE_BUF_SIZE);
- DMA_Cmd(DMA2_Stream5, ENABLE);
-
- }
- }