IBIS Macromodel Task Group

Meeting date: 27 April 2010

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 Herrick, Ansoft
  Chris McGrath, Synopsys
* Danil Kirsanov, Ansoft
  David Banas, Xilinx
  Deepak Ramaswany, Ansoft
  Donald Telian, consultant
  Doug White, Cisco Systems
* Eckhard Lenski, Nokia-Siemens Networks
  Eckhard Miersch, Sigrity
  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, Sigrity
* Kellee Crisafulli, Celsionix
* 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 Komow, Cadence Design Systems
  Richard Mellitz, Intel
  Richard Ward, Texas Instruments
  Samuel Mertens, Ansoft
  Sam Chitwood, Sigrity
  Sanjeev Gupta, Agilent
  Scott McMorrow, Teraspeed Consulting Group
  Shangli Wu, Cadence Design Systems
  Sid Singh, Extreme Networks
  Stephen Scearce, Cisco Systems
  Steve Kaufer, Mentor Graphics
  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, Mentor Graphics
  Vikas Gupta, Xilinx
  Vuk Borich, Agilent
* Walter Katz, SiSoft
  Wenyi Jin, LSI Logic
  Zhen Mu, Mentor Graphics

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Opens:

- None

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Call for patent disclosure:

- No one declared a patent.

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Review of ARs:

- Arpad to create new flow diagram for the clarification BIRD.
  - Will be discussed today

- Scott to rewrite clock ticks BIRD
  - Arpad has not heard from Scott
  - We will not vote on it today

- 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:

Arpad requested to discuss the AMI Flow diagrams:
- Todd has created a truth table
- Arpad showed the IBIS50AMI_TaskList spreadsheet
  - Some items have been rearranged
  - Rows 5-9 have been answered

Row 10: (whitespace)
- Arpad: Are newlines allowable whitespace?
- Todd: Newlines don't matter in these files
- John: The C language defines newlines as whitespace
- Walter: Whitespace is of concern only inside double-quotes
  - Quoted strings can have any kind of whitespace, which is preserved
- Arpad added "line termination sequences"
- Kumar: The only termination is the brackets
- Arpad: Subparameters need to be space separated
- Walter: There is no need to be consistent with .ibs files
- Mike: "line termination sequences" may not be the right phrase
  - How we define this depends on the context in which "white space" is used
  - Maybe we could refer to another spec such as that for C
- Todd: AMI records can span lines
  - Sometimes they are way too big for a single line
- John: We have a bug in the parser
- Kellee: Can we specify exactly which characters are whitespace?

Row 33: (parameter string passed to DLL)
- Arpad: Row 33 does not allow double quotes to be passed to the DLL
- Walter: Any ASCII characters can be in double quotes
  - The 120 character line limit was a mistake
- Kellee: It would help to define which ASCII characters are allowed
- Walter: IBIS defines the legal character set
- Todd: We should plan under the assumption it will be removed from the
  IBIS spec to another spec eventually

Row 15: (min/typ/max)
- Arpad: Have we defined default value well enough?
- Walter: If there is a list the default value must be a list member
  - The default must be a valid value "according to format"
- Arpad: Does the increment have to be positive?
- Walter: It doesn't matter, we always use the absolute value
  - The typ value is the anchor point
- Arpad: Do we start at the default value?
- Walter: We start at typ
- Arpad: The tool will start at typ and increment up to max
  - Then it goes down from typ to min
- John: Does it create a set or an ordered sequence?
- Todd: It creates a set that is between min and max
- Kellee: The language about min and max is not quite right
- Arpad added "closest to" to those limits
- Bob: It needs to be highlighted that the list is referenced to typical
- Arpad: We need to move on
  - We can discuss rows 15 and 16 by email

Arpad showed Todd's truth table in a spreadsheet:
- Arpad: rows 3 and 5 are equivalent
- Walter: Correct
  - Use_Init_Output is used only in conjunction with GetWave_Exists
- Todd: Can I run time domain simulation with a row 3 model?
- Arpad: Output from Init could be convolved to create a time domain waveform
- Ambrish: Use_Init_Output only makes sense when GetWave_Exists
- Todd: The returns from Init and GetWave are independent
- Arpad: Disagree that Use_Init_Output only makes sense when GetWave_Exists
- Walter: We should rename Use_Init_Output to "combine init output with GetWave output"
  - Use_Init_Output should not imply GetWave_Exists
- Ambrish: Agree
- Todd: Use_Init_Output only is relevant when both GetWave_Exists and Init_Returns_Impulse
- Arpad: Use_Init_Output is also relevant when you want to run TD from Init
- Ambrish: Not true
- Arpad: In row 3 we say Init_Returns_Impulse but don't use it
  - Init can still be used in TD analysis
- Todd: Is the purpose to tell if the impulse response is to be factored into TD waveform?
  - It is the equivalent of making the model a no-op
  - It makes no sense to allow only statistical analysis
  - A more strict definition might say that
  - This was not the intent
- Walter: I don't think that was our intent
- Todd: The comment added in row 3 needs to change
- Ambrish: We should not use Todd's truth table
- Fangyi: If GetWave_Exists=false then Use_Init_Output=true
- Ambrish: Not true
- Fangyi: That line is on page 8 of the BIRD 104 has that line
- Walter: We should remove that
- Bob: It's page 144 in the IBIS spec
- Todd: I see it at the top of page 145
- Fangyi: If GetWave_Exists=false we can use a linear model
- Todd: Literal interpretation is having only Init means use it to prepare
  - We need to agree we can do LTI TD simulation if there is Init and no GetWave
- Walter: We could say "If GetWave_Exists=false than Use_Init_Output has no meaning"
- Ambrish: That makes sense
- Todd: This truth table discusses things we need to agree on
- Arpad showed 3 statements to summarize the discussion
  - Use_Init_Output only to be used when GetWave_Exists
  - When GetWave_Exists=false Use_Init_Output is effectively true for LTI TD
  - Use_Init_Output=true for statistical
- Fangyi: Why not "If GetWave_Exists=false then Use_Init_Output=true"?
- Todd: I said When GetWave_Exists=false then Use_Init_Output=true
- Ambrish: Arpad's third point is not true
- Walter: Ambrish said for row 9 
  - For receiver not modified by impulse response when Use_Init_Output=true
- Arpad: Rows 8 and 6 should be identical
- Todd: In row 8 you are using an impulse repines that isn't there
  - Rows 2-7 could have don't care for Use_Init_Output
  - Except 7 and 9 are not don't cares
- Arpad: The results are the same but for different reasons

Next meeting: 04 May 2010 12:00pm PT

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IBIS Interconnect SPICE Wish List:

1) Simulator directives