[ibis-macro] Minutes from the 23 Jun 2009 ibis-atm meeting

  • From: "Mike LaBonte (milabont)" <milabont@xxxxxxxxx>
  • To: "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Mon, 29 Jun 2009 15:18:05 -0400

Minutes from the 23 Jun 2009 ibis-atm meeting are attached.

Mike
IBIS Macromodel Task Group

Meeting date: 23 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, Agilent
  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

------------------------------------------------------------------------
Opens:

Arpad:  Should we add a suggestion for clock_times calculation algorithm
  to the IBIS-AMI specification?
- Adding many clock time steps can accumulate significant error.
- Walter: Tools need to have correct order of evaluation
- Radek: Agree with Arpad
- Walter: Floating point engines should be able to add a million million
  numbers before losing accuracy
- Mike: A rational expression format may be more accurate
- Arpad: We need to work with what we have
  - We want to prevent model makers from making simple mistakes up front

AR: Arpad write a BIRD to clarify time period accuracy requirements

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

- No one declared a patent.

-------------
Review of ARs:

- 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

-------------
New Discussion:

User defined functions:
- Arpad: These may be useful with complicated expressions
  - HSPICE definition does not look complicated
- Walter: It is more complicated than it looks
  - This is for interconnect, with mostly computed numbers
- Mike: Agree with Walter
  - These files should be machine generated, not hand crafted
- Bob: This raises the bar for the required depth of HSPICE compatibility
- Radek: Can expressions include voltages and times?
  - Walter: We are not allowing that
  - Arpad: It is evaluated before the simulation starts, not dynamically
  - Mike: It could be difficult for simulators without the capability
    - V and I can be known only after a DC solution
  - Arpad: Dynamic evaluation 
- Bob: These are introduced by single quotes
  - That is HSPICE-specific
- We decided to not have user-defined functions

Built-in functions:
- Arpad: Will we have ternary operators?
- Mike: Does that allow non-linearity?
- Walter: These are evaluated before simulation
  - We should not have the ternary, but not if/else
- Arpad: This will make it harder to switch on different corners
  - A single circuit could use conditionals to implement typ/min/max
- Walter: The industry does not need this complication
  - Are interconnect model generator tools doing this today?
  - Arpad: Some customers are using parameters to select corner cases
  - Walter: For silicon yes, for interconnect no
- Mike: It would be good to have the input of interconnect model generators
- Walter: We can ask at DAC
- Bob: We are not sure if there will be a presentation on this
- Walter: I could create one
  - We will need Synopsys feedback
  - Will not put it one the web yet
- We decided to not have if/else/endif or ternary operator

Walter showed a "best practices" page:
- Avoid scaling
- Start all names with [a-zA-Z]
  - Arpad: We have a table spelling out more complex rules for this
  - Walter: These are recommended practices only
- Do not mix numbers and alphas in node names
  - For example, 1A and 1B are the same node in HSPICE

Walter showed the IBIS-IS document:
- Many external references can be deleted
- They mostly point to things that we don't need
- Some refer to tables that are on the same page
- Eliminating global parameters allows a lot of material to be deleted
- Reference to page 96: Do we want to pull that material in?
- The E element had some things that are really for the G element
  - These were moved to the G element

Arpad: Will we keep the items we are dropping in the document for a while?
- We will edit later after reading the minutes
- Things like conditionals are already removed
- Arpad: Walter could check if anything else needs to go
  - Walter: OK

AR: Walter will send out the updated document

Next meeting: 30 June 2009 12:00pm PT

--------

IBIS Interconnect SPICE Wish List:

1) Simulator directives

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  • » [ibis-macro] Minutes from the 23 Jun 2009 ibis-atm meeting - Mike LaBonte (milabont)