Re: Timing Requirements vs. Guranteed

Ed Casas (edc@ece.ubc.ca) Tue, 28 Nov 2000 12:46:47 -0800 

Date: Tue, 28 Nov 2000 12:46:47 -0800
From: Ed Casas <edc@ece.ubc.ca>
Subject: Re: Timing Requirements vs. Guranteed



Hi,

I'm not sure if this e-mail from Joe "Loser" Engineer is a joke,
but...

> What's the difference between timing requirements for
> inputs/outputs and guranteed responses?

This is explained in the lecture notes.  If the specification is
measured "to" (ends at) an edge on an output signal then it's a
guaranteed response.  If the specification is measured to an edge
on an input then it's a requirement.

You should also try to figure out what type of specification it
is (propagation delay, setup time, hold time, ...) to get a
better understanding of what's going on.

> I can't figure out how to do the expressions for the assignment
> as well because i cannot find guranteed responses to make my
> timing requirement therefore I figured that I must have my
> guranteed and requirements mixed up.

You may have to use clock periods in addition to other guaranteed
responses.  In a (very) few cases it may not be possible to
derive an expression because some guaranteed responses are not
given.

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