Ed,
That's a pretty broad topic. I have no doubt that your customers are
experiencing issues; it's been our experience that different model makers
and EDA vendors are interpreting key sections of the IBIS-AMI spec
differently, and that is affecting how models run and the results they
produce.
In our opinion, there are two parallel paths to solving this problem:
1) Work directly with model makers to understand why a *particular*
model doesn't work in a *particular* tool. In other words, the details
matter.
2) Identify and resolve weaknesses in the spec that affect model
robustness and portability - particularly areas where a model/tool can
produce different results and *still* conform to the spec (I like to call
this condition under-specified)
As you would expect, we do both. Obviously, we focus our efforts on the
EDA tool we have access to (ours) and seek to bring our learnings back to
the IBIS committee.
Bottom line, there's no easy answer to your question - if you're in a
position to help us create examples and guides, we'll take all the help we
can get!
Todd.
<https://mailsrv.sisoft.com/service/home/~/?auth=co&id=232523&part=2>
Todd Westerhoff
VP, Semiconductor Relations
Signal Integrity Software Inc. . www.sisoft.com
6 Clock Tower Place . Suite 250 . Maynard, MA 01754
(978) 461-0449 x24 . twesterh@xxxxxxxxxx
"I want to live like that"
-Sidewalk Prophets
From: ibis-bounce@xxxxxxxxxxxxx [mailto:ibis-bounce@xxxxxxxxxxxxx] On
Behalf Of Ed Sayre
Sent: Tuesday, June 9, 2015 5:25 PM
To: bob@xxxxxxxxxxxxxxxxx; ibis@xxxxxxxxxxxxx
Subject: [ibis] Re: BIRD175.2: Extending IBIS-AMI for PAM4 Analysis
Bob:
A number of folks that I communicate with have expressed great frustration
with the use of IBIS-AMI models in their simulators of choice. Are there
examples and a user guide which go beyond the specification?
ed
From: ibis-bounce@xxxxxxxxxxxxx <mailto:ibis-bounce@xxxxxxxxxxxxx>
[mailto:ibis-bounce@xxxxxxxxxxxxx] On Behalf Of Bob Ross
Sent: Tuesday, June 09, 2015 11:39 AM
To: ibis@xxxxxxxxxxxxx <mailto:ibis@xxxxxxxxxxxxx>
Subject: [ibis] Re: BIRD175.2: Extending IBIS-AMI for PAM4 Analysis
All,
On re-reading BIRD175.2, I have a few comments:
1. Both "PAM4_UpperThreshold" and "PAM4_Upper_Threshold" appear in
BIRD175.2.
(Same for *Center_Threshold and *Lower_Threshold.)
I would prefer using the underbar "_" for these parameters and also for
the *Offset parameters.
2. For the *Threshold parameters, the rule:
* If the Reserved AMI Parameter Modulation is set to "PAM4" and
these threshold values are not declared, the model maker shall assume that
the EDA tool may choose a value for each of these three parameters.
should be changed.
All three parameters definitions should be declared if Modulation is set
to "PAM4" with Value
or in a List. Otherwise we are using "implicit" parameter definitions in
IBIS-AMI on unpredictable
results between EDA tools. However, the EDA tool can re-assign the
values.
3. The defaults of 0.0 are OK for the *Offset* parameters, if they are
missing.
(I will be out today, so I may not be able to respond.)
Bob
From: ibis-bounce@xxxxxxxxxxxxx <mailto:ibis-bounce@xxxxxxxxxxxxx>
[mailto:ibis-bounce@xxxxxxxxxxxxx] On Behalf Of Mirmak, Michael
Sent: Friday, June 05, 2015 11:34 AM
To: ibis@xxxxxxxxxxxxx <mailto:ibis@xxxxxxxxxxxxx>
Subject: [ibis] BIRD175.2: Extending IBIS-AMI for PAM4 Analysis
An updated BIRD175.2, Extending IBIS-AMI for PAM4 Analysis, has been
submitted on behalf of Walter Katz, Mike Steinberger, and Todd Westerhoff
of SiSoft; Fangyi Rao of Keysight Technologies; Bob Miller of Avago
Technologies; and Hongtao Zhang of Xilinx. It will be discussed at the
next IBIS Open Forum teleconference.
The text of the BIRD can be viewed at
http://www.eda.org/ibis/birds/bird175.2.docx.
Michael Mirmak
Intel Corp.
Chair, IBIS Open Forum
http://www.eda.org/ibis/
