Dear Michael Zaidman,
In message 660c0f821002160556o71b9814dl3bb35f26ff5adfbb@mail.gmail.com you wrote:
You may of course do that - it's your local code after all. But I tend to believe that this does not make much sense. Interactive tests should be run at a time when interaction is supported, i. e. _after_ relocation to RAM.
You are right in general, but here we are targeting different purpose rather than interactively confirm pass or failure. I tried to explain it in this thread - "The general idea behind adding simplest user interface (what the GPIO LEDs are pretended to be) is to supply earlier possible indication about board status in the cases where board was stuck before serial console is available or in the field where there is not the serial console at all" and in my previous posting.
Yes, I know.
In order to relate on this indication we must be sure it is operating correctly. It could be done by observing diagnostics LEDs performing running "1" pattern or any different algorithm which user is expected. Only afterwards we may be sure that we correctly interpret number and result of specific POST test which is indicated on the diagnostics LEDs.
I have to admit that I don't understand your exact requirements. To me this makes not much sense. Classic system design would probably include a "lamp test" button where you can test the hardware - i. e. if all your LEDs / LED segments are working (but one might discuss if this is still needed with LED's - it certainly was useful with classic light bulbs that would burn through sooner or later).
A temporary display which disappears so you miss it if you don't look at the device in the right moment is not exactly the kind of user interface I would like for a function you seem to consider critical.
I know I repeat myself, but this sort of testing is something that should be done automatically, which automatically determined test results. An interactive test (user has to look at the device at the right moment and realize what some blinking LED means) is inappropriate. Just my 0.02 EUR.
Best regards,
Wolfgang Denk