IBIS Macromodel Task Group

Meeting date: 26 April 2011

Members (asterisk for those attending):
Agilent:                    * Fangyi Rao
                              Radek Biernacki
Ansoft:                       Chris Herrick
                              Danil Kirsanov
Ansys:                        Samuel Mertens
                            * Dan Dvorscak
                              Deepak Ramaswamy
                              Jianhua Gu
                            * Curtis Clark
Arrow Electronics:          * Ian Dodd
Cadence Design Systems:       Terry Jernberg
                            * Ambrish Varma
Celsionix:                    Kellee Crisafulli
Cisco Systems:              * Mike LaBonte
                              Stephen Scearce
                              Ashwin Vasudevan
Ericsson:                     Anders Ekholm
IBM:                        * Greg Edlund
Intel:                      * Michael Mirmak
LSI Logic:                    Wenyi Jin
Mentor Graphics:            * John Angulo
                              Vladimir Dmitriev-Zdorov
                              Zhen Mu
                            * Arpad Muranyi
Micron Technology:            Randy Wolff
NetLogic Microsystems:        Ryan Couts
Nokia-Siemens Networks:     * Eckhard Lenski
Sigrity:                      Brad Brim
                              Kumar Keshavan
                            * Ken Willis
SiSoft:                     * Walter Katz
                              Mike Steinberger
                            * Todd Westerhoff
Snowbush IP:                  Marcus Van Ierssel
ST Micro:                     Syed Sadeghi
Teraspeed Consulting Group:   Scott McMorrow
                            * Bob Ross
TI:                           Casey Morrison
                              Alfred Chong
Vitesse Semiconductor:        Eric Sweetman
Xilinx:                       Mustansir Fanaswalla

The meeting was lead by Arpad Muranyi

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Opens:

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Call for patent disclosure:

- None

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Review of ARs:

- Arpad update Out-InOut BIRD and send to Mike for posting
  - Done

- Bob update syntax clarification BIRD
  - In progress

- Ambrish start a BIRD on task list row 25
  - In progress, on hold

- Bob write a BIRD on correcting Table 1-3 in the spec.  (Row 23).
  - In progress, on hold

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New Discussion:

Arpad showed the Out-InOut BIRD draft:
- Arpad: We may be able to vote on this today
  - Red, blue, and green colors are used to mark different changes made
- Walter: SiSoft will vote no
  - We strongly recommend against it
  - The Jitter BIRD only uses Model_Specific Out/InOut for TX DCD
    - We can discuss it then
  - Sigrity back channel models use it
    - This would prevent them from using that model
  - This prevents innovation
  - Back channel has to use parameters that are not reserved
- Arpad: This does not prohibit any feature
  - It only makes them non-compliant
  - New BIRDs can be approved when they appear
- Todd: "Model_specific parameters ... must not be used" sounds prohibitive.
  - Agree with Walter
  - If all loopholes are to be closed then side files would be prohibited too
- Ken: Back channel is not totally precluded by this BIRD
- Walter: Why does the specification have to preclude this?
- Arpad: This only says it is not spec compliant
- Todd: It will not be obvious to everyone what is compliant and what isn't
  - We want to promote standardization and enable innovation in a controlled way
  - This says if models innovate they are not compliant
  - The alternative is to not use IBIS
- Arpad: A BIRD can be written for any innovation
- Walter: Why not say model makers are encouraged to write BIRDs?
- Todd: Using straight IBIS 5.0 is no risk
  - Using BIRDs slated for IBIS 5.1 would be low risk
  - Prototypes would have higher risk
  - Vendors should at least be recognized instead of criticized for innovating
  - At least there would be some continuity in how the change is made

- Walter: We should table this to next week
- Arpad: This has been discussed for weeks
  - We should vote
  - The final decision would be for the Open Forum anyway
- Ken: Tools would have to be in reactive mode if innovation is outside of IBIS
  - We have to get things in the spec faster
  - There is no efficient way to code for Model_specific parameters
- Walter: Are we trying to solve a problem that doesn't exist?
  - Has any model caused anyone to change their code for Out/InOut params?
- Arpad: It would be required to make the model work
  - The BIRD process is quick enough
- Walter: IBM and SiSoft presented at a summit 2.5 years ago about using Touchstone for
    analog models
  - This was needed to get the job done for a customer
  - The innovation was published over a year ago and in BIRDs 119-124
- Arpad: Analog models can't be understood from Opal
  - That used Info parameters in a non-standard way
- Todd: This BIRD is about Out/InOut, not Info
- John: It's a 2 way street
  - SiSoft has benefited from the standard
  - This has been a constructive process
- Todd: We have been committed to this standardization
- Ambrish: How can you tell it prevents innovation?
- Todd: It says models using this would not be compliant
- Ambrish: They would only be non-compliant
- Todd: That fact would be used against us by our competitors

- Arpad: We should develop a legitimate mechanism now
  - I am opposed to having a spec that allows meaningless functionality
- Todd: We could have had a registry convention to turn these into reserved parameters
  - Model_specific was because we had no way
- Walter: IBIS 5.0 still does not handle diff analog models properly
  - We should eliminate the need for these things by eliminating IBIS
    deficiencies
- Arpad: Reducing innovation is not the goal
- Todd: It is only the by product
  - We need a controlled way to innovate
- Arpad: Fixing innovation would be the next step
- Walter: We should not move forward until we understand how to fix innovation
- Ambrish: I don't see a problem with this paragraph
- Ken: It would only be non-compliant
  - You can't expect tools to code for anything we add in
  - We should not need a slew of new params for every innovation
  - Back channel should be implemented wit a minimum of new things

- John: This could cause problems like IBIS 5.0 AMI did
- Mike: This BIRD could be submitted without committee recommendation
- Arpad: I had started a BIRD with Info
  - Walter beat me to it
  - The tool does not know what to do with this
- Todd: We need to solve innovation
- Fangyi: If the tool uses this to change simulation we have no standard
- Walter: Motion to table until we deal with innovation
  (the motion was not seconded)

- Todd: Should my parameters be undeclared and proprietary?
- Ambrish: Walter said one model already does this
- Todd: My work on jitter etc. would be outlawed
  - There would be no way for me to innovate
- Fangyi: The standard supports innovation
  - You can create non-standard models first

- Todd: Using Touchstone is a good innovation example
- Ken: You only need IBIS 5 for that
- Walter: How can IBIS 5.0 do that?
- Arpad: ICM has it
- Walter: That allows only Berkeley SPICE
- Arpad: It would have been possible to use an ICM model for a package any
  time

- Michael M.: We have only a few minutes left
  - What do we need to decide?
- Ken: Whether to vote
  - Maybe we need a new place for experimental keywords

- Walter: Let's call it a registered parameter
- John: Adoption is not automatic just because things are registered
- Arpad: No Model_specific parameter has a description
  - The spec is wrong
  - SiSoft says this BIRD will short circuit innovation

- Todd: Innovation would be limited to IBIS releases
- Arpad: We should find a way to fix that
  - AMS was supposed to get us away from keywords
- Todd: The contract between model and simulator is fixed
- Fangyi: We are trying to avoid Opal becoming the standard

- Michael M.: Maybe an offline poll of vendors would help here
- Walter: IC vendors are not represented here
- Arpad: It would have a better audience in the Open Forum
- Michael M.: Anyone objecting can suggest alternatives
- Arpad: Walter did, but his name is removed from the BIRD now

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Next meeting: 03 May 2011 12:00pm PT

Next agenda:
1) Task list item discussions

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IBIS Interconnect SPICE Wish List:

1) Simulator directives
