STM32F407ZET6的片子，采用DMA进行串口发送，DMA部分相关固定配置如下：         DMA_InitStructure.DMA_BufferSize =  255;//固定要发送的字节长度
        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_VeryHigh;
        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在发送中断中，置完成标志位，下次发送时检查该标志位，发送完成则再次发送。
发送能正常发送，发送完成中断也能正常进，但每次发送时都会先进FIFO错误中断。何解？？？？

在配置完DMA之后，再使能串口触发DMA发送 该问题即可解决 每次DMA发送之侯，下次发送之前 关闭一下 串口触发DMA发送，使能DMA之后再将使能打开

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;   
FIFO失能，后面的配置有什么用？！

楼上的说的对，
既然FIFO都关闭了，
应该把FIFO的中断也关闭吧。

先签到下

In direct mode, the FIFO error flag can also be set under the following conditions:
• In the peripheral-to-memory mode, the FIFO can be saturated (overrun) if the memory
bus is not granted for several peripheral requests
• In the memory-to-peripheral mode, an underrun condition may occur if the memory bus
has not been granted before a peripheral request occurs
If the TEIFx or the FEIFx flag is set due to incompatibility between burst size and FIFO
threshold level, the faulty stream is automatically disabled through a hardware clear of its
EN bit in the corresponding stream configuration register (DMA_SxCR).