[ibis-macro] Minutes from the 12 Aug 2014 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
- Date: Thu, 14 Aug 2014 15:47:18 -0400
Minutes from the 12 Aug 2014 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 12 August 2014
Members (asterisk for those attending):
Agilent: Fangyi Rao
* Radek Biernacki
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
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
Teraspeed Consulting Group: Scott McMorrow
* Bob Ross
The meeting was led by Arpad Muranyi.
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Opens:
- Michael M: The interconnect meeting tomorrow is canceled.
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Arpad to review IBIS spec for min max issues.
- In progress
- Brad check within Cadence about overclocking approaches
- No report
- Arpad - Work with Randy to update BIRD 173.
- In progress, maybe next week
- Bob and Ambrish - Update BIRD 147.
- Can present results today
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New Discussion:
MinMax BIRD:
- Arpad showed a BIRD draft.
- Arpad: All spec sentences with min/max are copied here
- "NA" means typical is substituted.
- Certain places require NA to be used.
- If min or max is missing for anything the entire file should have NAs
- Mike L: It should be the entire model, not file.
- Bob: It's too hard to change a lot of models
- Radek: This would be for new models.
- Walter: This makes sense for I-V curves but not other parameters.
- You might have dv/dt for all corners and one I-V curve.
- Arpad: Can a min measurement be used with a typical simulation?
- Bob: Threshold values?
- Some are fixed, some vary with supply.
- Walter: An across the board rule is scary.
- Arpad: It seemed last week we wanted an across the board simple rule.
- One question is if there should be one statement in the spec or in many
places.
- Bob: There are both OK and questionable cases, depending on the parameter
combinations.
- We should have required 3 columns from the beginning.
- Arpad: We explicitly called for typical to be substituted for NA.
- Walter: Some things like current could be the same for all corners.
- Arpad: Using typical I-V will not match V-T min or max.
BIRD 128:
- Ambrish: The update has been forwarded to Michael M for posting as 128.1.
BIRD 147.1 and co-optimization:
- Ambrish showed draft 11 of the BIRD 147.1 update.
- Ambrish: File prefixes are now lowercase, and "ibis_" is reserved..
- Description changes have been made.
- "BCI" root name is reserved, private parameters must use another root.
- Walter: What tells us that AMI_Init will do optimization?
- Ambrish: The string returned will have (BCI ...)
- Walter: I would like a Boolean to say that it is supported.
- Ambrish: The Training parameter conveys that.
- Walter: Can it do both stat and TD?
- Ambrish: No
- The AMI files have 0, 1 or 2.
- Both TX and RX have to have the same value to do training.
- Walter: What is suggested here is not the only way to write a protocol.
- Ambrish: Other protocols would not be IBIS approved.
- Todd: What makes it IBIS approved?
- Ambrish: THE BCI file is created by the IBIS committee.
- Walter: The strings produced by the models would have to be approved.
- This mandates how statistical analysis must be done.
- There may be other ways.
- Ambrish: The BCI only gives the parameters.
- Todd: There is no checking of the strings produced by the model.
- We have no enforcement today of how DLLs use the strings passed.
- There is an assumption the models do what BCI says.
- Walter: 1.7.1 should say "Here is one way ...", but not be explicit.
- Ambrish: This gives the IBIS way of doing it.
- Walter: I reject that.
- Todd: Ambrish is saying the only comm method is to change taps iteratively.
- Ambrish: That will be the only IBIS approved way to do it.
- Todd: If the RX tells the TX to change 3 units it needs three calls.
- Ambrish: Send (-1 3)
- Walter: Where does it say I can do that?
- How does the RX know how far it can go?
- Todd: It can request a change, but that not not be implemented.
- How does the RX find out how much room there is to adjust?
- Walter: Does the protocol give the limits?
- Ambrish: No
- In time domain we only have increment and decrement
- Walter: PCIeG3 says it can send tap values.
- A BIRD would be needed for that.
- This BIRD could simply allow for other ways.
- Ambrish: That is valid.
- Or we could include both methodologies.
- Walter: There can be more ways.
- We should not need a BIRD for each.
- It should be part of the BCI approval process.
- This BIRD is forcing a methodology
- Todd: The BIRD proposes no enforcement so it's unenforceable.
- Walter: The approval process should not be constrained by these rules.
- Ambrish: Private protocols are allowed.
- Walter: Can a jitter knob be IBIS approved?
- Ambrish: No protocol talks about a jitter knob.
- Todd: Only BCI files get approved.
- We are pretending this is a standard but it's not.
- Ambrish: We have to specify this so the other side knows what we are sending.
- Todd: If a DLL doesn't respond correctly it won't work.
- This will be more hidden.
- Todd: There are protocols that communicate coefficients, not integers.
- Ambrish: That can be added.
- Walter: Or we could simply allow for other ways to communicate.
- Ambrish: Model makers would then have to read 2 specifications.
- Walter: But the EDA tool would not have to.
- Todd: This should be considered as a change to the BIRD.
- Ambrish: We will discuss it.
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Next meeting: 19 August 2014 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
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