串口DMA接收，加空闲中断，DMA没数据可读？

独舞洪荒 · 发表于 2014-11-12 15:36:10

用的是f205，因为系统需要50ms接收一次串口数据，所以使用中断的话，暂用硬件资源，没用操作系统。

问个问题，很奇怪，我使用的是DMA串口接收，加空闲中断。
结果我调试过程中，发送n次数据，只有第一次进入if(temp)，求解？也就是说DMA没接收到数据？

[mw_shl_code=c,true]void USART2_IRQHandler(void) { uint16_t temp=0; uint16_t i; if(USART_GetITStatus(USART2, USART_IT_IDLE) != RESET) { DMA_Cmd(DMA1_Stream5, DISABLE); temp = 256 - DMA_GetCurrDataCounter(DMA1_Stream5); if(temp) //次数只进入一次 { SysPostStack(uart2_receive_stack, (uint8_t*)USART2_RECEIVE_DATA, temp); } DMA_SetCurrDataCounter(DMA1_Stream5, 256); DMA_Cmd(DMA1_Stream5, ENABLE); i = USART1->SR;//????idle i = USART1->DR; } //USART_ClearITPendingBit(USART2, USART_IT_IDLE); }[/mw_shl_code]

我的DMA配置代码，如下：

[mw_shl_code=c,true]/* DMA1 Stream5 channe4 configuration USART2_RX*/[/mw_shl_code] [mw_shl_code=c,true] RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE); DMA_DeInit(DMA1_Stream5); DMA_InitStructure.DMA_Channel = DMA_Channel_4; DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)0x40004404; DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)USART2_RECEIVE_DATA; DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; DMA_InitStructure.DMA_BufferSize = 256; 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_High; DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable; DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull; DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single; DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single; DMA_Init(DMA1_Stream5, &DMA_InitStructure); USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE); DMA_Cmd(DMA1_Stream5, ENABLE);[/mw_shl_code]