RE: [IBIS] RE: [ibis-macro] Re: Your presentation at Asia Summit

From: Lynne D. Green <lgreen22_at_.....>
Date: Fri Nov 10 2006 - 16:35:01 PST
Hi, Arpad, Lance, et al, 

It gets worse than that.

Even if the HSPICE models are unencrypted, the model parameters are only
good in HSPICE's (hard-coded) model equations.  UC Berkeley SPICE is the
closest one can come to a standard SPICE.  But like so many college
projects, documentation and support are weak.

AMS can run about as fast as IBIS, and much faster than SPICE.  SPICE
macro-models run even slower than SPICE (more nodes, more non-linear
branches => slower simulation time).

Best regards,
Lynne


"IBIS training when you need it, where you need it."

Dr. Lynne Green
Green Streak Programs
http://www.greenstreakprograms.com
425-788-0412
lgreen22@mindspring.com


-----Original Message-----
From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Muranyi,
Arpad
Sent: Friday, November 10, 2006 2:19 PM
To: ibis@eda.org; ibis-macro@freelists.org
Subject: [IBIS] RE: [ibis-macro] Re: Your presentation at Asia Summit

Ian,

Does this mean that you don't
want SPICE in IBIS after all?
Or are you suggesting that we
develop a STANDARD SPICE?

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

-----Original Message-----
From: Dodd, Ian [mailto:ian_dodd@mentor.com]
Sent: Friday, November 10, 2006 2:17 PM
To: Muranyi, Arpad; ibis@eda.org; ibis-macro@freelists.org
Subject: RE: [ibis-macro] Re: Your presentation at Asia Summit

Arpad,

Such is the beauty of an International Standard such as VHDL-AMS.

Ian 

-----Original Message-----
From: ibis-macro-bounce@freelists.org
[mailto:ibis-macro-bounce@freelists.org] On Behalf Of Muranyi, Arpad
Sent: Friday, November 10, 2006 3:00 PM
To: ibis@eda.org; ibis-macro@freelists.org
Subject: [ibis-macro] Re: Your presentation at Asia Summit

Ian,

And what is the poor customer going to do if he gets an IBIS file from
Intel, say for a memory controller, that links to an (encrypted) HSPICE
model, and he gets another IBIS file from a memory chip vendor which links
to a TLsim model (that is incompatible with the HSPICE controlled
sources) and there is no simulator that can simulate the two models
together?

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

-----Original Message-----
From: Dodd, Ian [mailto:ian_dodd@mentor.com]
Sent: Friday, November 10, 2006 1:51 PM
To: Muranyi, Arpad; ibis@eda.org; ibis-macro@freelists.org
Subject: RE: [ibis-macro] Re: Your presentation at Asia Summit

Arpad,

I would only be really happy if it were an encrypted Eldo model :-)

 ... Ok before you all flame me, I was only joking!

We have always tried to make IBIS vendor neutral.
In my opinion, if we decide to support parameter passing, it must equally
support all of the major SPICE (or SPICE like) simulators. That includes
HSPICE, Spectre, Eldo, Tlsim etc (my apologies if your favorite commercial
simulator is not here).

I don't see a difference as to whether the SPICE netlist is partially or
completely encrypted.
Is there something I have missed?

Ian 

-----Original Message-----
From: ibis-macro-bounce@freelists.org
[mailto:ibis-macro-bounce@freelists.org] On Behalf Of Muranyi, Arpad
Sent: Friday, November 10, 2006 2:32 PM
To: ibis@eda.org; ibis-macro@freelists.org
Subject: [ibis-macro] Re: Your presentation at Asia Summit

Ian, and Lance,

Neither one of you said anything on how you would go about this SPICE
support, and which SPICE?

Even if we say that on the interface level in IBIS, [External Model] and
[External Circuit], there is no need to know which SPICE language is inside
the external SPICE file, what happens if I made an IBIS file that references
as encrypted HSPICE model and distributed it to my customers?
Would Mentor and Cadence be happy?

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

-----Original Message-----
From: Dodd, Ian [mailto:ian_dodd@mentor.com]
Sent: Friday, November 10, 2006 1:14 PM
To: lwang@cadence.com; Muranyi, Arpad
Cc: ibis@eda.org; ibis-macro@freelists.org
Subject: RE: [ibis-macro] Re: Your presentation at Asia Summit

Lance,

I agree with the majority of your statements.
There is a need to better support SPICE macro-modeling.

I support giving the High Speed user the option to use either SPICE
macro-modeling or AMS.
As part of this I support parameter passing into SPICE models (macro or
otherwise).

I do very much disagree with your comment about needing to be a rich company
to afford to purchase AMS enabled tools. At least one of the big three EDA
vendors is presently offering a full VHDL-AMS option with all of their SI
tools. The charge for the additional AMS functionality is around 15% of the
SI product base price. 

Incidentally, let's not let marketing and the internal politics of EDA
companies get in the way of the user having the best tools. Many EDA
companies have developed AMS simulation technology. Those that have not, can
almost certainly license it from third parties. When safeguards are put in
place, so that tools intended for High Speed Analysis cannot be used for IC
design, the EDA vendor has the opportunity to set a very aggressive price
for AMS functionality.

I have been very careful not to try to use this as a marketing platform.
I hope you take my statements in the way they were intended: about
technology and its availability, not about selling a particular brand.
Note again that, with the exception of your comments about the price charged
for AMS, I agree with your initiative.

Ian Dodd
Mentor Graphics Inc.

-----Original Message-----
From: ibis-macro-bounce@freelists.org
[mailto:ibis-macro-bounce@freelists.org] On Behalf Of Lance Wang
Sent: Thursday, November 09, 2006 1:23 PM
To: arpad.muranyi@intel.com
Cc: ibis@eda.org; ibis-macro@freelists.org
Subject: [ibis-macro] Re: Your presentation at Asia Summit

Hi, Arpad,
Thanks for reading my prez and asking so detailed questions about the
conclusions. :)

Let me give you some backgrounds for making this presentation first. 
As everyone noticed, PCIe/Serdes type devices are more and more shown in
current electronic market especially 2.5/3.125GHz devices. The first problem
the vendors met is how to deliver the SI models to their customers so they
can do the simulations accurately, fast and also IP protected since the
simulation is required for this kind of designs.
What they have in hands first is the Spice transistor-level models (mainly
HSpice compatible models). They would look for IBIS solutions as well for
these models. However, unfortunately, traditional IBIS can't correctly model
them. Then, people looked into IBIS [External model] in
4.1 and 4.2. What they found is that IBIS only allows Berkley-Spice (3f4?).
This is not what they look for. (I think I don't need to list the issues
using Berkley-Spice here.) Will AMS do the trick? Yes or No.
Yes, AMS is functional for this technology. No, not a lot of people
(companies) want to spend extra-cost for the tools expect some rich
companies. (These are not $9.99 products. Correctly me if I am wrong.) More
naturally problem is that there is no push button solution for AMS SI models
now. What did they end up? Using IBIS [External model] with Spice
transistor-level models. Please note these are NOT Berkley Spice models.
Also, there are a lot of parameter settings in PCIe models. For the ease of
use, Parameter passing is required for Spice [External model] even if IBIS
didn't allow them. 

In this stage, simulation performance and IP protection are the big concerns
for the IBIS "Advanced" Spice [External model]. The macromodeling is kicking
in solving these issues, I meant IBIS "Advanced" Spice Macromodeling.

Yes, the requirements from this presentation conclusion are somehow related.
When IBIS opens for "Advanced" Spice, parameter passing requirement can be
processed. However, "self-containing" capability should be required for IBIS
Macromodeling in general included AMS types as well.  

Thanks,

Lance Wang
Cadence Design Systems, Inc.
 

-----Original Message-----
From: ibis-macro-bounce@freelists.org
[mailto:ibis-macro-bounce@freelists.org] On Behalf Of Muranyi, Arpad
Sent: Thursday, November 09, 2006 1:28 PM
To: ibis@eda.org; ibis-macro@freelists.org
Subject: [ibis-macro] Your presentation at Asia Summit

Lance,

I read your presentation you gave at the Asia IBIS Summits and I would like
to ask you a couple of questions regarding your "IBIS future enhancement
requests" on the "conclusions"
slide (pg. 31).

http://www.vhdl.org/pub/ibis/summits/oct06b/wang.pdf

You are asking for opening the SPICE link in IBIS to other commercial SPICE
simulators, and consequently you are also asking for the parameter passing
capabilities for [External Model] (and probably [External Circuit] also)
which was not made available in the IBIS specification because Berkeley
SPICE does not have that capability.

Questions:

1)  The first sentence in Section 2 of the IBIS specification which is
entitled "Statement of Intent" says the following:

| In order to enable an industry standard method to electronically
transport
| IBIS modeling data between semiconductor vendors, EDA tool vendors,
and end
| customers, this template is proposed.  The intention of this template
is to
| specify a consistent format that can be parsed by software, allowing
EDA
| tool vendors to derive models compatible with their own products.

In other words, the IBIS specification was intended to provide a common
modeling language for the EDA industry.  Your request seems to be asking the
endorsement of proprietary SPICE languages in IBIS, which goes in the exact
opposite direction of the "IBIS philosophy" which was to eliminate the need
to make zillions of tool specific models for the same product.  How do you
see your request to be fulfilled?

2)  The very reason the IBIS macro modeling subcommittee spent about two
years to put together the IBIS macro modeling library was to solve this
problem.  We wrote a SPICE compatible library in the *-AMS languages so that
tools which cannot interpret the *-AMS languages could by substitution use
their own native SPICE equivalents.

See pg. 2 in the following presentation:
http://www.vhdl.org/pub/ibis/summits/mar06/muranyi2.pdf
See pg. 7 in the following presentation:
http://www.vhdl.org/pub/ibis/summits/feb06/westerhoff.pdf

Everything that you showed in the above presentation could have been
implemented with the IBIS macro modeling library.  Why are you not making
use of this library, and why are you requesting that features which are
already available in IBIS through the macro library be made available with
proprietary SPICE languages which is what we wanted to avoid with the entire
IBIS macro modeling initiative?

Thanks,

Arpad
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Received on Fri Nov 10 16:35:12 2006

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