IBIS Macromodel Task Group

Meeting date: 06 September 2016

Members (asterisk for those attending):
ANSYS:                      * Dan Dvorscak
                              Curtis Clark
Broadcom (Avago):             Xingdong Dai
                            * Bob Miller
Cadence Design Systems:       Ambrish Varma
                              Brad Brim
                              Kumar Keshavan
                              Ken Willis
Cisco:                        Seungyong (Brian) Baek
eASIC:                        David Banas
                              Marc Kowalski
Ericsson:                     Anders Ekholm
GlobalFoundries:              Steve Parker
IBM                         * Luis Armenta
Intel:                      * Michael Mirmak
Keysight Technologies:        Fangyi Rao
                              Radek Biernacki
                            * Ming Yan
Maxim Integrated Products:    Hassan Rafat
Mentor Graphics:              John Angulo
                            * Arpad Muranyi
Micron Technology:          * Randy Wolff
                              Justin Butterfield
QLogic Corp.:                 James Zhou
                              Andy Joy
SiSoft:                     * Walter Katz
                              Todd Westerhoff
                            * Mike LaBonte
Synopsys:                     Rita Horner
                              Kevin Li
Teraspeed Consulting Group:   Scott McMorrow
Teraspeed Labs:             * Bob Ross
TI:                           Alfred Chong


The meeting was led by Arpad Muranyi.

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Opens:

- Walter said Michael M had emailed back-channel questions.
- Arpad: Ambrish and Curtis emailed that they could not attend.

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Review of ARs:

- Walter submit [Pin Mapping] BIRD to Open Forum.
  - Done.
- Bob Miller submit Backchannel BIRD to Open Forum.
  - Done.

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No patents were declared.

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Review of Meeting Minutes:

- No Aug 30 minutes yet.

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New Discussion:

Michael M email about back-channel communication:
- Michael M: Colleagues had concerns about using files for communication.
  - Are I/O restrictions needed?
  - Bob Miller pointed out that it is not a live simulation, that the models
    are called at separate times.
- Walter: That is correct.
  - Synchronization might be every 1000 UI, for example.
- Bob M: Block size could theoretically be 1 UI but that would be silly.
- Michael M: With a large block size some events might be missed.
- Arpad: EDA tools determine block size.
  - There is no restriction that it must remain the same.
  - What if the block size changes from call to call?
- Walter: We will be requiring only a minimum.
  - The exact number should not be critical.
- Arpad: Can this change after initialization?
- Walter: Maybe the suggested block size should apply only during training.
- Bob M: This is used for latency during message passing.
  - The EDA tool could choose a smaller block size for memory reasons, for example.
- Walter: The model might not send messages every block.
- Arpad: We should clarify that it is only for the training period.
- Bob M: We could do that.
  - The overhead of a GetWave call is small.

- Mike L: File caching can be a problem, particularly with Windows.
  - Has this approach been tried?
- Bob M: Some testing has been done.
- Walter: Caching should be a problem only for separate processes.
- Arpad: We should not count on the TX and RX being in the same process though.
- Mike L: The BIRD appears not to preclude using sockets.
- Walter: This is much like the original BIRD 147.


IBIS 6.2 BIRDs:
- Walter showed an updated IBIS 6.2 BIRDs spreadsheet.
- Bob: BIRD A is not BIRD 184, D is 184.
- Walter: BIRDs F, G, and I all have to do with pin reference.
  - The question is what to do when the component has no reference pin.
  - Bob and Radek are working this out.
- Bob: We have not connected to discuss that yet.
- Walter: There are two worlds:
  - One in which everything is floating.
  - One which is ground based.

- Arpad: A number of BIRDs were untabled in the previous Open Forum meeting.
  - It is not clear if we should discuss them here.
- Walter: BIRD 128 was untabled because BIRD 147.1 doesn't need it.
  - BIRD 180 relates to BIRDs 125, 163, and 164. Maybe BIRD 165 too.
  - It says there are no joins or splits between pins and models.
  - You can't have the same pin twice.
  - The parser flags these as errors.
  - BIRD 180 makes that illegal.
  - It's not clear how an EDA tool should handle such a case.
  - Arpad would prefer to avoid voting on BIRD 180 until BIRD 125 is voted down,
    but that is waiting for the new Interconnect BIRD.
  - The Interconnect BIRD is inconsistent with BIRDs 125, 163, and 164.
  - Those should be voted down sooner rather than later.
- Arpad: The question is if we discuss them here.
- Mike L: It would be good to have them on this agenda.
- Walter: It helps for IBIS to be consistent with the parser.
- Arpad: We could put BIRD 180 on this agenda.

- Bob R moved to put BIRD 180 on the agenda.
  - I would not change the parser to handle multiple pins.
- Mike L seconded.
- Without objection the motion passed.

- Walter moved to remove BIRD 147.1 from the tabled BIRDs list.
  - This was to delete, not to untable.
- Bob R seconded.
- Without objection the motion passed.

- Bob R: Is the New Redriver Flow BIRD an update to the Redriver flow BIRD?
- Walter: There is no BIRD yet, just a PowerPoint.
  - It overlaps with BIRD 166.
  - It adds multiple Impulse Response inputs and outputs.
  - They could be combined into one BIRD.
- Bob R: A draft BIRD was sent last October.
- Walter: I have not seen it posted.
- Michael M: There should be no interaction between BIRDs 147.1, 166, and this new BIRD.
- Walter: There will be none.

- Walter: Motion to adjourn.
- Bob R: Second.
- Arpad: Thank you all for joining.
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Next meeting: 13 September 2016 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
