IBIS Macromodel Task Group

Meeting date: 15 February 2011

Members (asterisk for those attending):
Agilent:                    * Fangyi Rao
                            * Radek Biernacki
Ansoft:                       Chris Herrick
                              Danil Kirsanov
Ansys:                      * Samuel Mertens
                              Dan Dvorjak
                              Deepak Ramaswamy
                              Jianhua Gu
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
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:

- Walter: MM is investing new file formats
  - We might want to use DOC for easier revisions

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Call for patent disclosure:

- None

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Review of ARs:

- Ambrish draft BIRD for relationship between Type and Format
  - TBD

- Arpad follow up with Kukal on BIRD 121 include file
  - TBD

- Arpad check with Kumar and Vladimir on crosstalk in AMI_Init
  - Done

- Walter send BIRDs 116-125 position email to list
  - Done

- Bob draft BIRD for Tables
  - In progress

- Bob investigate strings issue
  - In progress

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New Discussion:

Arpad showed an email exchange between Bob and Atul:
- Arpad: This is similar to row 25 in our task list
- Bob: This was partially dealt with in BUG 109
  - Other items should be amendments to BIRD 127
  - We have to clarify that Tap is an integer represented as a float
- Ambrish: I looked at BIRD 127
  - Any new BIRD will depend on BIRD 127 anyway
  - BIRD 127 should be modified instead
- Bob: BIRD 127 is submitted already
- Arpad: But we can still change it

AR: Bob check BIRD 127 for type clarification possibilities

Arpad showed Bob's draft BIRD for Tables:
- Bob: Adds AMI_Version
  - Keeps Use_Init_Output with a note
  - Ignore_Bits was mistakenly an Output
  - Maybe "No Jitter" should be "0"

AR: Bob send draft Tables BIRD to Mike for posting

Arpad: Should task list row 25 go into BIRD 127 too?
  - BIRD 127 is already large
- Ambrish: It might take only 3 sentences
- Bob: Maybe it should be another table

Arpad: We had a question if Init should modify for crosstalk impulse response
  - We need to run a normal analysis first
  - Then run crosstalk analysis
  - This may become complicated
  - RX may sometimes have a peaking filter
    - This would need to modify the impulse response too
    - That gives us one more reason to allow modification
  - Should we remove the statement from the spec?
- Arpad showed the IBIS spec 3.1.2.1 impulse_matrix section
  - The statement that might be removed is:
  "The aggressor columns of the matrix should not be modified"
- Radek: Why do the aggressor TX Inits have to modify their impulse responses?
- Walter: Ken suggested we add text to say what tools and model makers must do
  - Arpad showed 5 TX and 5 RX
  - All are both victims and aggressors
  - The matrix should have the response from the primary to all others
- Arpad showed his "impulse_matrix and crosstalk in IBIS-AMI" slide
- Walter: You have to assemble 5 x 5 impulse responses
- Ken: Not all are needed if only the result at the middle RX3 matters
- Arpad: Walter is right since TX1 coefficients depend on what RX1 sees
- Fangyi: Only TX1 to RX1 and TX1 to RX3 are needed
- Ambrish: Why TX1 to RX1?
- Ken: All 5 channels must be characterized so TXs can set tap coefficients
- Ambrish: Each TX wants the best behavior for it's own RX
  - Each one will look at this in a vacuum
- Arpad: Tap coefficients are not set to control crosstalk
- Ken: Each TX optimizes it's own channel then provide IR for crosstalk
- Bob: Will they actually all be the same, since there are more adjacent channels?
- Arpad: This came up because the spec says Init should not modify
  - We seem to agree it should be removed
  - Should the spec describe what to do?
- Radek: Yes, the spec says nothing about handling multiple channels
- Ken: We can do this with simple verbage
- Arpad: We should continue this discussion by email

AR: Ken draft language to clarify handling of multiple channels

Arpad showed the task list:
- Ken: Which is the Jitter BIRD?
- Arpad: BIRD 123
- Walter: The Table type was created for jitter PDF
  - The Table format is:
    - 1st column is an ordinal number
    - 2nd column is time in UI
    - 3rd column is probability
  - Type UI would be meaningless for probability
  - Some use Table as In, not Info
  - We pass entire tables in using a single string
  - That is a better way to do it
  - Table should always be Info, for TX jitter
- Arpad: Could we start a BIRD on this?
- Ken: What happens to models that use Table as Input today?
  - It is legal
- Walter: It is not legal
  - The first field has to be a number
  - This has to be settled before we write a BIRD
- Ken: Table should not be limited that way
- Ambrish: The spec doesn't say rows should begin with integers
- Walter: Section 10 of the BIRD requires "(param_name ..."
  - But table begins with numbers
  - If it were allowed table could have only one row
- Arpad: We should discuss this by email

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Next meeting: 22 Feb 2011 12:00pm PT

Next agenda:
1) Task list item discussions

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IBIS Interconnect SPICE Wish List:

1) Simulator directives
