Minutes from the 22 August ibis-atm meeting are attached.
The following BIRD revisions were discussed during the meeting:
ID#Issue TitleRequesterDate
SubmittedDate
AcceptedSupporting
Version
192.1 Clarification of List Default Rules
<http://ibis.org/birds/bird192.1.docx> Michael Mirmak, Intel Corp. August
22, 2017, August 23, 2017
192 Clarification of List Default Rules
<http://ibis.org/birds/bird192.docx> Michael
Mirmak, Intel Corp. August 22, 2017
The following document, which was discussed during the meeting, was
previously posted to the ATM work archives.
*DATE* AUTHOR <http://ibis.org/atm_wip/archive-author.html> ORGANIZATION
<http://ibis.org/atm_wip/archive-org.html> TITLE
<http://ibis.org/atm_wip/archive-title.html> FORMATS
15-AUG-2017 Radek Biernacki Keysight Technologies BIRD 158.6 draft 3 (zip
<http://ibis.org/atm_wip/archive/20170815/radekbiernacki/BIRD_158_6_draft_3.zip>
)(docx
<http://ibis.org/atm_wip/archive/20170815/radekbiernacki/BIRD%20158.6%20draft%203/BIRD_158.6_draft3.docx>
)
IBIS Macromodel Task Group
Meeting date: 22 August 2017
Members (asterisk for those attending):
ANSYS: Dan Dvorscak
* Curtis Clark
Broadcom (Avago): Xingdong Dai
Bob Miller
Cadence Design Systems: * Ambrish Varma
Brad Brim
Kumar Keshavan
Ken Willis
eASIC: David Banas
Marc Kowalski
Ericsson: Anders Ekholm
GlobalFoundries: Steve Parker
IBM Luis Armenta
Trevor Timpane
Intel: * Michael Mirmak
Keysight Technologies: Fangyi Rao
* Radek Biernacki
Ming Yan
Maxim Integrated Products: Hassan Rafat
Mentor, A Siemens Business: John Angulo
* Arpad Muranyi
Micron Technology: * Randy Wolff
Justin Butterfield
SiSoft: * Walter Katz
Todd Westerhoff
* Mike LaBonte
Synopsys: Rita Horner
Kevin Li
Teraspeed Consulting Group: Scott McMorrow
Teraspeed Labs: * Bob Ross
TI: Alfred Chong
The meeting was led by Arpad Muranyi.
--------------------------------------------------------------------------------
Opens:
- Arpad noted that Curtis had informed him that he would not be able to attend
the meeting August 29th. Arpad said he would need a volunteer to take minutes
at that meetings.
-------------
Review of ARs:
- Radek to send out an updated BIRD 158.6 draft 3 with changes as discussed.
- Done.
- Arpad noted that Radek's new version contained more changes than he had
expected to see based on the discussions at the August 8th meeting.
- Radek noted that at the August 8th meeting he had said he would feel free
to add new parameters to give the model maker more ways to describe the
content/usage of the package models. He said the version he sent out after
the August 15th meeting was consistent with his statement on August 8th.
- Arpad agreed, and Arpad and Radek noted that Walter had sent out a follow
up proposal after Radek had emailed draft 3.
- Randy to send C_comp_model_Using_IBIS_ISS_BIRD_rev1_WIP.docx to Mike L for
posting.
- Done.
--------------------------
Call for patent disclosure:
- None.
-------------------------
Review of Meeting Minutes:
- Arpad: Does anyone have any comments or corrections? [none]
- Radek: Motion to approve the minutes.
- Randy: Second.
- Arpad: Anyone opposed? [none]
-------------
New Discussion:
BIRD158.6:
- Arpad: After Radek posted his updated version, then Walter proposed one that
removed everything related to Ts4file_Boundary and moving the connection
points from buffer terminal to pad, or pin.
- I'd like to get Radek and Walter's comments and then open up for discussion.
- [sharing side-by-side Walter's and Radek's versions]
- Radek: The right side is what I posted and we discussed last week.
- My version contains additional parameters to provide package model
description information that was suggested by Bob Miller. We need to get
his opinion.
- Walter then decided to remove the pin and pad locations and all the
packaging options.
- I think it's best to give the model maker a way to specify this package info
for the EDA tool and the user.
- We need to figure out the best way to fulfill the needs of the model maker.
- Walter: The original concept of BIRD158 was a shortcut for [External Model].
- [External Model] is for the buffer (it is a replacement for [Model]).
- It's what people do for their on-die S-parameters.
- Then some combination of Radek and others decided to allow the Touchstone
file information to go to the pin.
- As a practical matter, no one does this, and it just complicates things.
- I didn't object at the time because I was going to just have it go to
the buffer by default. Everyone makes their models this way, and it
wouldn't be a problem.
- But then we got into all these involved discussions about packaging and
interactions with the Touchstone file.
- The bottom line is if the Ts4file includes the package then you should put a
zero package model in the IBIS file. Then you're done. I think we should
go with simplicity. There's no need to complicate this BIRD and the parser
with additional keywords that no one will use.
- On-die S-parameters have been around almost since the beginning of IBIS.
- People have been doing this for ten years. Let's keep it simple.
- Let's not make EDA tools worry about dealing with odd combination when the
model maker can simply make the package model compatible with what's in the
Ts4file.
- Bob R.: I support Walter's approach of simplicity.
- This BIRD has spun out of control. Deleting all packaging related
parameters is the best solution for a number of reasons.
- You can always cascade the Ts4file with the existing IBIS package model and
make the package model zero.
- EDA tools can give options.
- I think Walter's version should become BIRD158.6 draft4.
- Arpad: I too prefer Walter's version.
- I feel similarly that Ts4file was simply supposed to replace [Model].
- In light of BIRD189, it would simplify things to consider this BIRD 158
to just connect to the buffer terminal. For legacy IBIS package models
that's the same as the pad (since there was no on-die interconnect). But
considering the BIRD189 interconnect model that may specify on-die
interconnect, it simplifies things to consider this BIRD to connect to the
buffer terminal.
- Radek: I would like to hear from Bob Miller.
- He's the one who wanted the pad as an option and the ability to provide a
separate Touchstone file for packaging information. I think we have to do
what's best for the model makers. If we don't accommodate the way he does
his measurements then we are in trouble.
- Arpad: If we have BIRD189 style models then I don't think he will be prevented
from doing what he wants to do.
- Walter: I don't like to be the one to announce this, but Bob Miller has taken
early retirement from Broadcom and is no longer their representative.
- I move to vote on whether I should prepare my version as BIRD158.6 draft4
and send it to the ATM. Next week we can vote on whether to recommend it
to the Open Forum.
- Bob R.: I second. I would like a roll call vote.
- Radek: I can work with either proposal. I will abstain until we hear from
Bob
Miller.
- Arpad: We have a motion and a second.
- Roll Call Vote:
ANSYS - abstain
Cadence - abstain
Intel - abstain
Keysight - abstain
Mentor - Yes
Micron - abstain
SiSoft - Yes
Teraspeed Labs - Yes
- Arpad: What does this vote mean?
- Radek: I think the motion passes. We have a record of the vote.
- Walter: I'll prepare BIRD 158.6 draft 4 before the next ATM meeting.
- Bob R.: Could Mike L. go back and add cumulative revision history to draft 4?
- It's missing from the recent previous versions.
- Arpad: Walter needs to start from an earlier version that only has "buffer
terminal" in the figures.
- Radek: I had an earlier version that included the various figure changes, like
Vp and Vn in the Tx figure, but did not yet include anything other than
"buffer terminals" in the figures. Walter can start from there.
BIRD 192: Clarification of List Default Rules.
- Michael M.: This BIRD resulted from a brief email thread I started that
related to Format List.
- As currently described, the default value to use from a List may be
ambiguous.
- If the first item in the list is considered the default value (as in the
initial description of List itself, List <default value> <value> <value>...)
it's not clear if this "default value" should be a duplicated member of the
existing list or if it should be a separate member.
- If the (Default xxx) specification is used, it's not clear how that
interacts with the List statement that the first value is the default.
- We have found that different tools interpret this differently.
- We introduce new text to clarify the intent:
- You can use a duplicated value from the list as the first entry (<default
value>).
- But the <default value> need not be a duplicate of another entry in the
list.
- If (Default xxx) is used, it overrides the first entry and provides the
default value.
- Ambrish: The first entry (<default value>) is simply an entry in the list.
- Arpad: I think the <default value> is separately listing something already in
the list. Otherwise, we could have just said <value> for the first
entry, and stated that the first value is the default value.
- Radek: I thought it was clear that if (Default xxx) were specified then it
would override the first value.
- I think we should clarify whether duplicate entries are still allowed in the
example in the last sentence with the (Default xxx) value:
(List 0 1 2 3 4)(Default 2)
- Walter: That example is exactly why we left the optional Default specification
in for List. Sometimes you don't want the first entry in an ordered
list to be the default. That last sentence example properly
demonstrates the original intent.
- Michael M.: Perhaps it would be clearer to just say:
List <value> <value> <value>...
- We can then say that the first value in the list is the default (if (Default
xxx) is not specified).
- Arpad/Curtis: If you change the first entry to <value>, what do we do with the
possibility of duplicates.
- Ambrish/Bob R./Walter: Unlimited duplication of the same value in a list is
always permitted.
- Bob R.: The parser will complain if a (Default xxx) specifies a value that is
not a member of the list.
- Walter: I suggest Michael M. can make a BIRD192.1 with this change and submit
it to the Open Forum.
- Walter: Motion to adjourn.
- Curtis: Second.
- Arpad: Thank you all for joining.
AR: Walter to create BIRD158.6 draft 4 with his version that removes the
Ts4file_Boundary and related parameters.
AR: Mike L. to add cumulative revision history to Walter's BIRD158.6 draft 4
and post it.
AR: Michael M. to create BIRD192.1 with the discussed change of the first item
in the List description from <default value> to <value>.
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Next meeting: 29 August 2017 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
