Subject: Commentary on Bob Wards suggestion:

From: Kellee Crisafulli <[email-masked]>
Date: 15 Mar 94 04:08:04 EST

To: all the ibis forum
From: Kellee Crisafulli, Hyperlynx
Re: Bob Wards mail:
Bob:
In looking over some of the BIRDS before the last forum call, the
question occured to me that if we are putting voltage thresholds into
the input models for the sake of timing analysis ( which I agree with
fully! ) should we also have, probably optional, annotation of the setup
and hold times for clocked devices for the same purpose?  If we view
ibis models as some kind of "electronic data book", then it would seem
natural to include these times, possibly under an optional [Timing]
keyword.  This would give enough data all in one place to flag
violations.  I doubt that there is enough data to assess the metastable
behviour possible if the violation occurs, and I am not at all sure we
want to put that much data in the model.  It gets too much into the
specifics of the circuitry, as well as not being particularly amenable
to measurement apart from simulation.  Does the forum feel this warrants
a BIRD?

Hello Bob.

We have discussed this one before with the consensus at the time
that this would extended IBIS into a much larger set of problems
and complications.  The goal of a full "DATA BOOK" specification
for a device is a big one.  The very next thing is a full
functional description (boolean logic) and timing description.
It explodes quickly.  We have many many roads to travel to do
really good job on basic signal integrity.  For example we don't
model turn-on and turn-off time of clamp diodes.  

For revision 2 and 3, I believe we should stick with creating
signal integrity models.  (Input/Output buffer information
specification)

For the future all things are possible....

Have a great day,  Kellee

---

From: "Hobbs, Will" <[email-masked]>
Date: Tue, 15 Mar 94 08:24:19 PST

Ibisians,

I tend to agree with Kellee.  I think there are enough dragons to slay (birds to
slay dragons, don't they?) in the signal integrity and flight time arenas.  I 
fully support making IBIS a part of a larger electronic data sheet 
specification, but feel we should keep our present focus until we have reached a
point of diminishing returns.  If IBIS were to eventually grow into the 
electronic data sheet, that would be fine, but I hesitate to devote much time to
that now.

Will

To: all the ibis forum

Hello Bob.

Have a great day,  Kellee