Order above chaos(rom unstability)

Ed Casas (edc@ece.ubc.ca) Mon, 13 Nov 2000 15:25:00 -0800 

Date: Mon, 13 Nov 2000 15:25:00 -0800
From: Ed Casas <edc@ece.ubc.ca>
Subject: Order above chaos(rom unstability)



> The unstable output of my rom depends on the order that I
> declare the instruction values.  I fixed my erroneous write
> signal by switching my rom memory assignments around.  This
> doesn't seem logical and is angering because you can't
> logically know that this is going to work.  There must be a way
> to get a stable rom output.  Can we clock the rom so that it's
> stable?  It's not a real simulation but would act more
> realistically than this " rom value bounce" that I'm
> experiencing.  Anyway, my simulation works but I would like it
> if it did not have to rely on the order that I write my rom
> instructions.

I don't understand your question.  The order of the clauses in a
selected assignment (except for "others") should not have any
effect on the behaviour.

Perhaps the "unstable" behaviour you are seeing is the result of
something else?  If you are seeing a lot of glitches then perhaps
your simulation clock rate is too high?

-- 
Ed Casas   edc@ece.ubc.ca   http://casas.ece.ubc.ca   +1 604 822-2592