What happens differently between reset and code upload?


I'm having some trouble with multiple SPI devices on my board.

-With a radiation detection device, I often (but not always) have to reset the board once to get SPI to work. -With my screen, reset doesn't do it, I have to re-upload code before it will respond.

My guess is that this has something to do with the chip enable lines not being high during reset, but I still don't understand why the screen would only respond after reuploading code.

There is a third SPI device, a DAC, and it works perfectly every time. All three devices use different SPI modes if that's of any significance.

Post your code and your schematic. Add pullup resistors on the chip select lines so nothing is active on the SPI pins during reset condition when all IO pins are inputs and just floating.

Which board?