IBIS Macromodel Task Group

Meeting date: 30 June 2009

Members (asterisk for those attending):
  Adge Hawes, IBM
  Ambrish Varma, Cadence Design Systems
  Anders Ekholm, Ericsson
* Arpad Muranyi, Mentor Graphics Corp.
  Barry Katz, SiSoft
* Bob Ross, Teraspeed Consulting Group
  Brad Brim, Sigrity
  Brad Griffin, Cadence Design Systems
  Chris McGrath, Synopsys
  David Banas, Xilinx
  Deepak Ramaswany, Ansoft
  Donald Telian, consultant
  Doug White, Cisco Systems
  Eckhard Lenski, Nokia-Siemens Networks
  Essaid Bensoudane, ST Microelectronics
  Fangyi Rao, Agilent
  Ganesh Narayanaswamy, ST Micro
  Gang Kang, Sigrity
  Hemant Shah, Cadence Design Systems
  Ian Dodd, consultant
  Jerry Chuang, Xilinx
  Joe Abler, IBM
* John Angulo, Mentor Graphics
  John Shields, Mentor Graphics
  Ken Willis, Cadence Design Systems
  Kumar Keshavan, Sigrity
  Lance Wang, Cadence Design Systems
  Luis Boluna, Cisco Systems
* Michael Mirmak, Intel Corp.
* Mike LaBonte, Cisco Systems
  Mike Steinberger, SiSoft
  Mustansir Fanaswalla, Xilinx
  Patrick O'Halloran, Tiburon Design Automation
  Paul Fernando, NCSU
  Pavani Jella, TI
* Radek Biernacki, Agilent (EESof)
* Randy Wolff, Micron Technology
  Ray Comeau, Cadence Design Systems
  Richard Mellitz, Intel
  Richard Ward, Texas Instruments
  Samuel Mertens, Ansoft
  Sam Chitwood, Sigrity
  Sanjeev Gupta, Agilent
  Shangli Wu, Cadence Design Systems
  Sid Singh, Extreme Networks
  Stephen Scearce, Cisco Systems
  Steve Pytel, Ansoft
  Syed Huq, Cisco Systems
  Syed Sadeghi, ST Micro
  Ted Mido, Synopsys
  Terry Jernberg, Cadence Design Systems
  Todd Westerhoff, SiSoft
  Vladimir Dmitriev-Zdorov
  Vikas Gupta, Xilinx
  Vuk Borich, Agilent
* Walter Katz, SiSoft
  Zhen Mu, Cadence Design Systems

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Opens:

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Call for patent disclosure:

- No one declared a patent.

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Review of ARs:

- Arpad write a BIRD to clarify time period accuracy requirements
  - TBD

- Walter will send out the updated document
  - Done

- Todd: Write IBIS s-param BIRD
  - Still working on it

- Arpad:  Write parameter passing syntax proposal (BIRD draft)
          for *-AMS models in IBIS that is consistent with the
          parameter passing syntax of the AMI models
          - TBD

- TBD:    Propose a parameter passing syntax for the SPICE
          - [External ...] also?
          - TBD

- Arpad:  Review the documentation (annotation) in the macro libraries.
          - Deferred until a demand arises or we have nothing else to do

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New Discussion:

IBIS parser AMI-related feedback sent by Michael Mirmak:
- IBIS5 parser developer Atul sent questions on AMI parsing
- Walter showed the questions and his answers
- Question: Line length limit for AMI files?
  - Walter: A 120 line limit would make it more convenient to edit
  - Bob: Does the spec imply a 120 char limit?
  - Walter: It says there is a 120 char limit in description fields
    - This is so it would not wrap in forms
  - Michael M: That may apply only to the description field
  - Arpad: Is there a need to limit the entire file?
    - With this format it can be easier to have long unwrapped lines
  - Michael M: We have to have explicitly stated rules
    - There is no limit except for the description
  - Walter: The AMI spec will have a number of issues like this
    - We need a clarification BIRD
  - Arpad: What needs to be clarified?
  - Walter: Line length constraints need to be clarified
- Question: Why does // appear in an example?
  - Walter: That is a C language example, not AMI
- Question: Why are the AMI comment rules listed outside the AMI file section?
  - Michael M: Page 143 "Algorithmic Model End A M"
    - Subtrees can be in any order in the file
    - This gives the definition for contents of the AMI file
    - Rules about | comment char here apply only to AMI files
- Question: What other syntax is permitted in AMI files (tab chars, etc)
  - Walter: There is a BNF description
    - It does not clearly define whitespace
    - Tabs and spaces should be whitespace
  - Arpad: Does IBIS cover that?
  - Michael M: Section 3 clearly covers all syntax rules
  - Arpad: Are EBD and PKG the same?
  - Michael M: Those contents can be in an IBS file, so have the same rules
  - Walter: We need to define whitespace for AMI
  - Bob: This will be clarified in section 10
  - Arpad: "Whitespace" is mentioned only at [Model Selector]
    - IBIS never defines it as a whole
    - Michael M: It is define by exclusion
      - Chars are given by ASCII number
  - Arpad: Should we define it here?
    - No, we agreed
  - Bob: 100 tabs followed by description would be a problem
- Question: Should first token in AMI file be the filename
  - Walter: Some tools may have character set restrictions
  - Mike L: Can it have double-quotes and embedded space?
  - Walter: No, that is allowed only in text fields

Arpad brought up an email from Walter:
- Walter: Init_Returns_Impulse and GetWave_Exists can not be True simultaneously
  - Init is for the frequency domain
  - GetWave is for time domain
- Bob: They can't both be false either
- Mike L: If both are True GetWave might not be called even though it exists
- Walter: No, peaking and DFE filters might be implemented in each part
  - That is not a recommended practice though
- Walter: Reserved parameters tell how the model operates
  - We initially did not have a default
  - The assumption was first in list was default
  - The other entries were not checked for consistency
  - The default is really a hard value, not something that could change
  - It is better to use a real value instead of a default
  - We need a clarification BIRD
- Arpad: What if the user wants other values?
  - Walter: Model specific parameters are passed into the DLL
    - You would not pass a list of values

Walter showed the AMI BNF:
- Arpad: This standardizes how to pass into the DLL
  - Otherwise DLLs would have proprietary input formats
- John: The syntax says you need to have a tree
  - The DLL might be lazy about honoring that
  - Does it need 2 branches, "reserved" and "model specific"?
  - Room for a disconnect between the tool and DLL
- Walter: It says somewhere don't send reserved to the DLL
  - John: Agree
- Walter showed AMI 3.1. .6
- Arpad: It says "all the input from the IBIS AMI parameter file"
- Walter: That needs to be clarified
- Walter: Not all combinations of Value/Corner/List/Range/Default are OK
- Bob: We will need warning messages in the future
- Bob: The meaning of NA is a text issue
  - It is not used as actual syntax in all places
- Walter: This can be a different font in a PDF file
- Bob: We are fixing the spec as well as the parser
  - We might do a BIRD in the short term, not leave lingering questions
- John: A lot is unsaid in the spec

Arpad: Do we have all the answers for Atul?
- Michael M: Have enough, but will have the group review it

Arpad: Is IBIS-IS ready for summit presentation?
- Bob: It can be posted as a work in progress
- Walter: I will clean up the notes and editorial marks

AR: Walter clean up IBIS-IS for summit presentation

Next meeting: 7 July 2009 12:00pm PT

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IBIS Interconnect SPICE Wish List:

1) Simulator directives