IBIS Macromodel Task Group

Meeting date: 05 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
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
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:

- None

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Call for patent disclosure:

- None

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Review of ARs:

- Arpad post Crosstalk BIRD draft
  - Done

- All review draft

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

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

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New Discussion:

Arpad showed the Crosstalk BIRD draft:
- Arpad: Radek suggested changing the wording of impulse units
  - Is it v/s or v-s?
- Radek: It is different in time domain
  - Only in digital do we drop the "per volt"
  - We should say it right or remove it
  - This is really voltage impulse response
- Arpad showed an email from Vladimir Dmitriev-Zdorov
  - This explains the v/s derivation
- Radek: This paragraph should be in the document
  - Or just don't use units
  - This goes beyond what impulse response is
- Arpad showed an email from Radek
- Walter: Is this about channel response or TX response?
- Radek: Nowhere do we go beyond the classical definition of IR.
- Walter: IR should be unit-less
  - Since a 1V input is used, technically volts are involved
  - But then voltage is divided back out
- Radek: Yes it is v/v
- Ken: Kumar said it should be v/s
- Bob: Has the serdes industry defined this incorrectly?
- Scott: It should be v/v, transfer function 1/s
- Arpad: Currently the BIRD says v/s
  - Who wrote this?
- Walter: Either me, Ambrish, Kumar ...
- Ken: We could call it "voltage impulse response" as Radek suggested
  - Can we vote on it?
- Arpad: This has enough changes to put off a vote
- Radek: I had suggested other changes
  - Need a change to row_size
  - The number of rows is the number of aggressors
- Arpad: We should take this offline

Arpad showed the Usage OUT and InOut BIRD:
- Arpad: A few paragraphs have been added on page 1
- Ambrish: We should say if simulation results should change as a result
- Walter: We have to be careful
  - That would apply to jitter parameters
- Ambrish: This is about model specific parameters
- Arpad: That may be OK
- Walter: There are backchan params that will affect simulation
  - These are kind of reserved
- Arpad: This is about model specific parameters
- Walter: They may become reserved
- Radek: We should decide how to classify these parameters
- Ken: This side data should just be written to a text file
- Arpad: The BIRD does not specify how the tool should do it
  - Some do not like the idea of models writing files
  - Standard formats would be needed
- Walter: Until a format BIRD exists it is non-standard
- Ken: This is model specific
- Walter: BIRD 121 has that
  - DLLId gives the file name
- Ken: If files are used is this Out param provision needed?
- Walter: IBIS 5.0 models would need it
- Ambrish: The output does not have to be in any particular format
- Walter: It does, the BNF specifies it
- Arpad: The paragraph I'm highlighting explains what tool vendors should do
  - We should add another statement to this
- Scott: It should also say that current or future results must not be
  modified
  - Anything that does that should be a reserved parameter
- Bob: EDA tools should not modify model specific parameters
- Radek: They should not act upon them
- Walter: Model specific parameters should all become reserved eventually
  - That may take long enough that some would not want to wait
- Scott: The intent is to shorten the cycle
  - While model specific there should be a debate about it
  - Not everything will go in the spec
- Walter: The process for getting into IBIS has to be accelerated
- Scott: No, the problem is getting info about these ideas early enough

Arpad: The form of our spec is rigid, keyword based
  - A language would be better
  - *-AMS languages are good
  - When we started the macromodel group I thought we would go that way
  - We made a big mistake with these keywords
- Walter: AMS can add keywords transparent to IBIS
  - The AMI clarification effort began two years ago
  - But it was put off
  - IBIS triangle:
    - Vendors, minimally represented here
    - EDA tools
    - Users
- Scott: Languages have to do with meaning, not algorithm
  - This is important when a EDA tool is used
- Arpad: What is the meaning of a resistor?
  - It is well defined in ISS
- Radek: If you have a subckt you have to know how it is to be used
- Arpad: With a language the spec would not have to be updated so much
- Scott: For example, we have to agree on the meaning of each jitter parameter
  - It is a painful process
  - It has been better since Arpad took over

Ambrish: We should say these output parameter strings are optional
- Walter: Meaning a model with no output does not need the string?
- Ambrish: Just that the model may output nothing
- Radek: If the Parameter is there it should produce a string
- Walter: The parameter is ** so it has to point to something
  - It should not be a null pointer
  - But it could point to a null string
- Ambrish: It should be able to do nothing
- Walter: It's not hard to return a null string

AR: Arpad add null output language

Arpad showed an email from Mike Steinberger:
- Arpad: We need to settle on language about arrays
- Ambrish: Existing models should continue to work
  - I wrote language that should work
  - All multi-row tables require row names
- Bob: My alternative does not require that
- Ambrish: I haven't read that yet
- Arpad: We need to focus on one proposal at a time
- Bob: I added an extension for single row tables with no parentheses
- Walter: Maybe Ambrish and Bob could work to agree on this
  - I won't object to the result

Arpad: Walter should rewrite BIRD 123.1 for OUT/InOut for the next meeting
- Walter: OK
- Scott: Could we have block diagrams for TX and RX
  - This would show where jitter params go
  - Some HSSCDR slides are good templates

AR: Walter rewrite BIRD 123.1

Walter: BIRD 122 should be a good solution now

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Next meeting: 12 Apr 2011 12:00pm PT

Next agenda:
1) Task list item discussions

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IBIS Interconnect SPICE Wish List:

1) Simulator directives
