I have a very strange problem with a Nucleo-F091RC board. I've been playing around with a serial
program just to print messages via the uart, just to get the first project started. I noticed
as long as I was programming the board and resetting it without removing the power (USB cable) from the board
everything worked fine. But when I removed the power (USB cable) and the reconnected the power to the board
it stopped working. With my DSO I noticed the uart TX line worked briefly, then the cpu stopped, no amount
of resetting could get this app working again, I had to reprogram the cpu to get it to work.
Is this some sort of sleep or stop mode thing going on?