IBIS Macromodel Task Group

Meeting date: 10 October 2023

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Amazon:                       John Yan
ANSYS:                      * Curtis Clark
                            * Wei-hsing Huang
Aurora System:                Dian Yang
Cadence Design Systems:     * Ambrish Varma
                              Jared James
Google:                       Hanfeng Wang
                              GaWon Kim
Intel:                      * Michael Mirmak
                              Kinger Cai
                            * Chi-te Chen
                              Liwei Zhao
Keysight Technologies:        Fangyi Rao
                              Majid Ahadi Dolatsara
                              Stephen Slater
                              Ming Yan
                              Rui Yang
Marvell:                      Steve Parker
Mathworks (SiSoft):           Walter Katz
                              Graham Kus
Micron Technology:            Justin Butterfield
Missouri S&T:                 Chulsoon Hwang
                              Yifan Ding
                              Zhiping Yang
Rivos:                        Yansheng Wang
SAE ITC:                      Michael McNair
Siemens EDA (Mentor):       * Arpad Muranyi
                            * Randy Wolff
Teraspeed Labs:             * Bob Ross
Zuken USA:                    Lance Wang

The meeting was led by Arpad Muranyi.  Curtis Clark took the minutes.

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Opens:

- Arpad noted that Michael had a new BIRD proposal "Pin Name Fields Extension"
  to discuss.
  
- Arpad observed that the workload in ATM is currently light, now that Kinger's
  PSIJ Sensitivity BIRD has been submitted as BIRD226.  Arpad asked whether we
  should consider using the ATM meeting for editorial work on the upcoming
  Touchstone 2.1.  Arpad noted that the Interconnect task group currently has
  two major proposals it could continue working on: port mapping and pole-
  residue format.  He asked whether we should consider working on the editorial
  process for Touchstone 2.1 in the ATM meeting, so Interconnect could continue
  working on the two new proposals.  Bob said he would prefer to set the two
  proposals aside for the time being and continue to use the Interconnect
  meeting to work on the editorial issues for Touchstone 2.1.  Arpad said this
  was just a question/suggestion, and we can consider how to use the ATM meeting
  time slot in the future.
  
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Review of ARs:

Michael: Send out draft10 of the [AMI Test Data] proposal including more
         feedback from the ATM meeting.
         - Done.  Michael had sent out drafts 10, 11 and 12.
         
Michael: Develop a full syntactically complete example demonstrating the
         [AMI Test Data] proposal.
         - In progress.  Michael said he would work on this after we get the
           proposal itself more settled.

--------------------------
Call for patent disclosure:

- None.

-------------------------
Review of Meeting Minutes:

Arpad asked for any comments or corrections to the minutes of the October 3rd
meeting.  Michael moved to approve the minutes.  Bob seconded the motion.
There were no objections.

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New Discussion:

AMI Test Data proposal:
Michael reviewed draft12, which had been sent to the ATM list prior to the
meeting.  He said that draft10 included the changes discussed at the previous
meeting, draft11 corrected an error in the keyword hierarchy tree, and draft12
contained editorial changes Arpad had suggested.  Michael noted two references
to "block size", which had not previously been defined, and said he had added
two new sentences defining block size in terms of the wave_size parameter.

Michael reiterated that he agreed with Ambrish's suggestion that he create a
full syntactically complete example.  He said he thought it had been hard to
find all the relevant information by reviewing the rest of the specification.
Arpad agreed and said that he had reviewed IBIS 7.2 to see what it said about
waveform input and the number of columns passed in and out of AMI_GetWave.  He
said he didn't find language explicitly stating that a column of time points is
not provided, though he said everyone apparently understood that.

Curtis noted that the Golden_waveform_file section contained a sentence,
regarding the number of columns of data, that only applied to the Statistical
Type simulation, wherein the Golden_waveform_file contained the expected output
of the AMI_Init call.  Michael and Arpad agreed.  Curtis said he thought the
definition of Golden_waveform_file left room for confusion because it was still
overloaded (it contained different information depending on whether the Type was
Statistical or Time_domain).  He asked whether we should remove this overloading
and replace Golden_waveform_file with two different subparameters, each of which
would be specific to one Type of simulation.  Arpad agreed.  Michael said we
could break Golden_waveform_file into two subparameters, and he suggested
Golden_impulse_file for the expected impulse response returned by AMI_Init.

Ambrish, Arpad and Curtis said Golden_waveform_file should be required for
Time_domain and illegal for Statistical.  Golden_impulse_file should be required
for Statistical and optional for Time_domain.  If the model maker chooses, they
can provide a Golden_impulse_file in the Time_domain case, and it will be
compared to the output returned by AMI_Init when it is called prior to the first
call to AMI_GetWave.  The group discussed whether Golden_impulse_file should be
prohibited if the AMI Reserved Parameter Init_Returns_Impulse is false.  Arpad
suggested that we should not make the prohibition.  He said we might want to be
able to test and confirm that the model is not mistakenly modifying the impulse
response in a case in which Init_Returns_Impulse is false.

Arpad had an additional suggestion regarding parameter names.  He said he didn't
think "impulse" was sufficiently precise and "impulse response" would be better.
Michael and the group agreed, and Michael said he would change Input_impulse_file
to Input_IR_file and add a Golden_IR_file subparameter.  Michael said he would
create a draft13 incorporating the changes.

Pin Name Fields Extension:
Michael noted that he had received several offline inquiries and requests that
we increase the specification's 5-character limit on pin names.  Additionally,
he reported that Kyle Lake of Cadence had raised the same issue in the most
recent Open Forum meeting.

Michael said pin names are now often machine generated and represent more than
the old data book pin names.  He said the proposal is to change the maximum
length of pin names from 5 to 20 characters.  He said that the change itself is
simple, but pin names are used in 10 other keywords, 9 of which have an
explicit field length limitation.  He said one option was to simply change the
explicit field length limitation from 5 to 20 in all cases.  He suggested that
an alternative might be to remove the per parameter limitations altogether and
just use the 1024-character overall line length limit.

Curtis said that the ibischk parser currently relies on size allocations based
on the various field length limits, and removing them altogether would create
complications for the parser.  He noted however, that the specification should
not be driven by parser development considerations.  Arpad said he thought it
best to go with the quick and simple 5 to 20 change for now.  We can revisit the
issue later if this change results in requests to increase other field lengths
as well.  Michael agreed with this approach and said draft1 of the proposal
contains the simple approach.

Randy asked whether we also want to expand pin names beyond alphanumeric
characters.  Michael and Arpad agreed that "_", for example, would be useful.
However, Arpad suggested that we handle that with a separate BIRD and keep it
decoupled from this length change.

Michael said draft1 did not require any changes based on the discussion in
today's meeting.  Arpad asked everyone to review it.

- Curtis: Motion to adjourn.
- Michael: Second.
- Arpad: Thank you all for joining.

New ARs:

Michael: Send out draft13 of the AMI Test Data proposal including more feedback
         from the ATM meeting.

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Next meeting: 17 October 2023 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
