DMA 每次只能接收256字节的问题

zhcy周 · 发表于 2017-2-9 10:12:33

PC机串口助手向芯片发数据，DMA每次中断只能接收256字节，发送字节如为260字节，就会两次进入中断，第一次接受256字节，第二次接受剩下的4字节改变DMA_BufferSize的值也没有用[mw_shl_code=applescript,true]/* DMA1 Channel5 (triggered by USART1 Rx event) Config */
DMA_DeInit(DMA2_Stream5);
DMA_InitStructure.DMA_Channel = DMA_Channel_4;
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)USART1_RECEIVE_DATA;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_BufferSize = UART_RX_LEN;
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_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;//2»¿afifo
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

DMA_Init(DMA2_Stream5, &DMA_InitStructure);
DMA_ITConfig(DMA2_Stream5, DMA_IT_TC, ENABLE);
DMA_ITConfig(DMA2_Stream5, DMA_IT_TE, ENABLE);

/* Enable USART1 DMA RX request */
USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);
DMA_Cmd(DMA2_Stream5, ENABLE); [/mw_shl_code]