RE: [IBIS-Users] VHDL-AMS Model

Lee,

The biggest difference between (legacy) IBIS and VHDL-AMS models
is flexibility. First, the IBIS v4.1 specification allows you to
use VHDL-AMS, Verilog-AMS models as external models, that's why
I refer to the older IBIS capabilities as legacy IBIS.

So the biggest problem with legacy IBIS was that the algorithms
were all predefined, and the IBIS file would just give you data
for those algorithms. Every time there was a change in the behavior
of the buffers we wanted to model we had to come up with a new
keyword and this took a prohibitively long time.

VHDL-AMS and Verilog-AMS are more like programming languages.
You can write equations almost any whichever way you want.
Therefore basically sky is the limit as far as modeling is
concerned.

This is a wonderful thing, because all those limitations that
existed in legacy IBIS models can be done away without possibly
having to change anything in the spec any more. On the other hand,
this may make it somewhat more difficult for the model maker,
because they will have to learn the language, and they will also
need to learn how to translate a certain behavior they observe
into the form of equations. This may not necessarily have to be
a big concern, though, because I believe that there will be many
models written in these languages which will be used as templates,
so that by providing parameters for them they could be used for
many devices as long as they belong to the same general family.

I hope this helps you to understand what these languages can do.

Thanks,

Arpad
=================================================================

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of lee yang
Sent: Sunday, January 30, 2005 9:35 PM
To: ibis-users@eda.org
Subject: [IBIS-Users] VHDL-AMS Model

Hi,

Recently I heard about another behavioral model call VHDL-AMS, can anyone
please give some background about it?
Since we already have IBIS model, what is the reason we need to use VHDL-AMS
model instead? What is the pros and cons compared to IBIS model?
Thanks and appreciate if someone can shed some light.

-Lee Yang

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Received on Tue Feb 1 09:21:35 2005