[ibis-macro] Minutes from the 02 Sep 2014 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
- Date: Wed, 03 Sep 2014 17:37:46 -0400
Minutes from the 02 Sep 2014 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 02 September 2014
Members (asterisk for those attending):
Altera: * David Banas
ANSYS: Dan Dvorscak
* Curtis Clark
Avago (LSI) Xingdong Dai
Cadence Design Systems: * Ambrish Varma
Brad Brim
Kumar Keshavan
Ken Willis
Ericsson: Anders Ekholm
Intel: Michael Mirmak
Keysight Technologies: Fangyi Rao
* Radek Biernacki
Maxim Integrated Products: Hassan Rafat
Mentor Graphics: John Angulo
* Arpad Muranyi
Micron Technology: * Randy Wolff
Justin Butterfield
QLogic Corp. James Zhou
Andy Joy
eASIC Marc Kowalski
SiSoft: * Walter Katz
* Todd Westerhoff
* Mike LaBonte
Synopsys Rita Horner
Teraspeed Consulting Group: Scott McMorrow
* Bob Ross
(Note: Agilent has changed to Keysight)
The meeting was led by Arpad Muranyi.
------------------------------------------------------------------------
Opens:
- Mike will not be able to attend next week
- Curtis will take minutes.
- Arpad:
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Radek work with Walter and Ambrish on BIRD 128.1 clarifications.
- Done
- Arpad send double quote BIRD draft to Mike for posting
- Done
- Mike post double quote BIRD draft
- Done
- Arpad send MinMax BIRD draft to Mike for posting
- Done
- Mike post MinMax BIRD draft
- Done
- Ambrish investigate other ways to communicate tap coefficients
- Ambrish would like to discuss today.
- Arpad to review IBIS spec for min max issues.
- In progress
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New Discussion:
BIRD 128.1:
- Arpad: Were Radek's comments incorporated?
- Radek: It was too late.
- Arpad: Then it can not be voted in the next Open Forum meeting.
BIRD 147
- Ambrish motioned to untable BIRD 147.
- Bob seconded the motion.
- There were no objections.
- Ambrish showed BIRD 147_draft12.docx
- Ambrish described changes.
- Integers are used to specify different Training mode
- There is a separate Init mode.
- A coefficient passing method is described.
- Arpad: How does the information get from TX to RX?
- Also what happens when the increment sizes are incompatible?
- Ambrish: It tries until a satisfactory result is achieved.
- Arpad: Should the granularity be communicated?
- Ambrish: It will go to the nearest valid value when it has to.
- Arpad: Will the TX report what was actually used?
- Ambrish: Yes.
- Arpad: The RX may send requests and the TX reports the value has not changed.
- Walter: This is peripheral to the PCIeG3 spec.
- The BCI details do not belong in BIRD 147.
- The communication mechanism should be in this BIRD.
- Why should a new BIRD be needed to create a new "ibis_*" standard protocol?
- Ambrish: The BCI file specifies the protocol.
- Walter: This may not work for fiber channel, for example.
- How does the TX advertise the constraints on tap coefficients?
- TX Init could generate a BCI branch, and the RX could send one back.
- This would be documented for each of the flows.
- Ambrish: It could be done in the first GetWave.
- Use_Init_Output ???
- Todd; Walter wants to optimize using Init and GetWave in the same run.
- This BIRD outlaws that.
- Ambrish: They can't be used in the same simulation.
- That is similar to the Use_Init_Output flow, which was deprecated.
- Walter: They can.
- Todd: Knowledge gained in Init processing might help GetWave.
- The BIRD has training for Init-only and GetWave-only.
- Ambrish: Multiple Training modes can be used.
- Todd: That requires models to retain settings from Init, but the BIRD doesn't
allow that.
- Walter: The spec allows the RX to optimize itself in Init, then in GetWave.
- Ambrish: Where is that specified?
- Todd: It is not explicitly allowed, but is not disallowed.
- Ambrish: Init and GetWave are supposed to be used separately.
- Todd: The spec allows them to be used together.
- Walter: Pages 172-173 of IBIS 6.0 describes how this can work.
- It says RX Init in time domain can contain an optimization algorithm.
- Ambrish: Do others agree with this?
- Todd: In bit-by-bit simulation GetWave will be used to get the eye.
- There is no reason not to get the eye from Init too.
- Walter: IBIS page 176 says both can be used.
- Todd: Terms like "simulation output" are not precise.
- Simulations can be "jump started" with data from Init.
- Ambrish: This BIRD is written literally using what IBIS 6 specifies regarding
Init and GetWave flow for the same model.
- Todd: We disagree.
- Ambrish: You are trying to have the BIRD support something that your tool
implemented.
- Walter showed IBIS 6 page 172 and 173.
- Walter read the language in the paragraph between those pages.
- Todd elaborated on how both Init and GetWave are used in time domain flow.
- Ambrish: My BIRD should not have to specify that.
- What you are doing is not part of the reference flow or application
scenarios
described in the specification.
- Todd: We do not want it disallowed.
- Ambrish: Models can implement PCIeG3 using this.
- Walter: This can be accomplished by passing BCI branches.
- Much of what is in the BIRD can be left up to the protocol.
- Otherwise it may take time to find we don't support other protocols.
- Ambrish: All but PCIeG3 require only increment/decrement.
- Walter: Fiber channel uses coefficients.
- Arpad: Would this BIRD as is allow ?? in the GetWave function?
- Todd: The flow described had punting in Init and training in GetWave.
- Arpad: Is it possible?
- Todd: Yes, but with a performance penalty.
- Ambrish: The question is if we move communication to the BCI file.
- Then we would have another document to read to implement the back-channel
communication.
- It would be better to have it all in the IBIS specification.
- Walter: We don't want to have to wait for IBIS 7.
- Todd: This should be discussed within Cadence.
- Ambrish: Others should weigh in too.
- Arpad: This will be on the agenda next week.
- Walter: Radek may wish to discuss it with Ambrish.
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Next meeting: 02 September 2014 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
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