片子是smt32F407 程序目的是通过UART4接收数据，积攒到5个的时候，由CAN按顺序发出，采用DMA doublebuffer模式。
现在遇到一个问题，buffer2的时候CAN发出的数据全是0，buffer1正常，发送数据的数目也正常

代码如下
[mw_shl_code=c,true]void DMA1_Stream2_IRQHandler(void) { if(DMA_GetITStatus(DMA1_Stream2,DMA_IT_TCIF2)!=RESET) { if(DMA_FreeBuffer_No==1) { DMA_FreeBuffer_No=0; DMA_ClearITPendingBit(DMA1_Stream2,DMA_IT_TCIF2); k=0; for(k=0;k<13;k+=3) { j++; Can_send(0x0203,UART4_RECIEVE_DATA[k],UART4_RECIEVE_DATA[k+1],UART4_RECIEVE_DATA[k+2],0,0,0,0,j); Delay(4000); } j=0; } else { DMA_FreeBuffer_No=1; DMA_ClearITPendingBit(DMA1_Stream2,DMA_IT_TCIF2); n=0; for(n=0;n<13;n+=3) { j++; Can_send(0x0204,UART4_RECIEVE_DATA2[n],UART4_RECIEVE_DATA2[n+1],UART4_RECIEVE_DATA2[n+2],0,0,0,0,j); Delay(4000); } j=0; }}}[/mw_shl_code] [mw_shl_code=c,true] DMA_DeInit(DMA1_Stream2); DMA_StructInit(&DMA_InitStructure); DMA_InitStructure.DMA_Channel = DMA_Channel_4; DMA_InitStructure.DMA_PeripheralBaseAddr = UART4_DR_Addr; //UART4_DR_Addr; DMA_InitStructure.DMA_Memory0BaseAddr =(uint32_t)UART4_RECIEVE_DATA; DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; DMA_InitStructure.DMA_BufferSize =ReBufferSize; 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_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_Stream2, &DMA_InitStructure); DMA_ITConfig(DMA1_Stream2, DMA_IT_TC, ENABLE); DMA_Cmd(DMA1_Stream2,ENABLE); DMA_DoubleBufferModeConfig(DMA1_Stream2,(uint32_t)UART4_RECIEVE_DATA2,DMA_Memory_0); DMA_DoubleBufferModeCmd(DMA1_Stream2,ENABLE); DMA_FreeBuffer_No=1;[/mw_shl_code] [mw_shl_code=c,true]int main(void) {NVIC_Config(); TIM_Config(); CAN1_Config(); DMA_Config(); while(1) {}}[/mw_shl_code]