I have a STM32 discovery board configured in slave mode receiving commands over SPI. When it receives a specific command byte, it activates DMA and sends back a set number of bytes back. I have a print statement at the beginning of my rx_isr function. I've noticed that when I receive the command byte, DMA is activated and begins to work (confirmed with the logic analyzer) but my rx_isr is called an additional 4 times. I would assume that since the DMA controller is now handling the SPI communication, I shouldn't receive any more calls to my isr. Does anyone have an idea what might be causing this?