[nheft]

I agree that your observations on interrupt enables and UART state on power-up are on target.

We saw pretty much the same results with or without the camera connected. The camera gets power from one of the PWM outputs so it has to come up after the RC does.

According to IFI the user uP gets data from the Master via a serial SPI interface. I don't know if there is any error checking in the user uP but I suspect not.

Six weeks was not going to be enough time to run this investigation into the ground and still be able to perform our remaining tasks, so I elected to work around the problem as I described in my last post.