Subject: Re: FW: EIAJ home page

From: "Charles Hymowitz" <[email-masked]>
Date: Tue, 14 Apr 1998 10:36:28 -0800

Thanks John. I looked at the EIAJ prED -5302 standards page on I/O
Interface Model Project Group. The pdf file for the standard doesn't
have all the fonts embedded so its kind of hard to download but
attached is the letter I sent the webmaster. What do you (and
others) think of my conclusion??

Dear prED -5302 Standards Webmaster
We are about to post a free utility to convert IBIS models into SPICE
models on our web site; a very important utility that is missing from
most SPICE users software. So we are very interested in the SPICE 
side of things. We would, in future, like to support the I/O modeling 
standard.

But one big problem, unless I am missing something with regard to the
proposed syntax, is that you are using non-standard Berkeley SPICE
syntax for the MOSFET element. I don't know who proposed this but it
won't work with anyone's SPICE simulator (except the one who proposed
the syntax I imagine)

Therefore this will slow acceptance of this standard dramatically
unless one of three things happen:

1) someone modifies the MOSFET code or B element behavioral model code
in Berkeley SPICE 3 to accept the syntax (then every SPICE vendor
could adapt the free Berkeley code into their simulator) or 

2) someone creates an XSPICE model (public domain AHDL available from
Georgia Tech Institute) using C code (again, then every SPICE vendor
could adapt the XSPICE code into their simulator) 

3) someone creates a utility to convert the prED-5302 model code into
a SPICE 2G.6 or SPICE 3 style model.

The problem with 3) is that you can't easily do table models in
SPICE2G syntax which is the only compatible standard SPICE syntax, and
SPICE 3 doesn't support a table model. Therefore unless 1) or 2) are
accomplished it appears that this "standard" will not become one.

Charles Hymowitz - V.P. Prod. Dev.
Intusoft
email: [email-masked], CompuServe: [email-masked]
Web: http://www.intusoft.com
Tel. (310) 833-0710, Fax (310) 833-9658
P.O. Box 710, San Pedro CA. 90733-0710

Please visit our web site @ http://www.intusoft.com for more information
and lots of SPICE goodies.

---

From: Fred Balistreri <[email-masked]>
Date: Tue, 14 Apr 1998 12:22:15 -0700

> and lots of SPICE goodies.

The syntax is a proposal that can unify and null out some of the 
objections IC vendors have in giving out Spice models. It is true that
this is a new model and Spice vendors will have to impliment this in
their particuliar brand of Spice. Once done the model is portable in
any Spice that supports it. And there lies the advantage. There is no
standard for Spice. Therefore Berekley models are supported as they
evolve but not in the Berekley form. Hspice routinely modifies both
the model parasitics and syntax for example. They then may "fix" some
bugs and whala a non-standard model that only Hspice can support. There
are certain advantages in everybody's Spice. And I'm sure EDA vendors
want to keep it that way to distinguish and differentiate themselves. 
This proposal if adapted can become a standard for Spice vendors. It
will take some work on the part of the Spice vendors just like it took
work to support IBIS models in any Simulator. There are Spice vendors
who do support IBIS by the way. Again each Spice simulator takes 
advantage of the features implimented in their Spice to accomplish this.
Bob Ross posted an example IBIS Spice behavioral model that can be used
in most generic Spice programs. 

Best Regards,