[ibis-macro] Minutes from the 19 Feb 2013 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 19 Feb 2013 22:32:25 -0500
Minutes from the 19 Feb 2013 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 19 Feb 2013
Members (asterisk for those attending):
Agilent: Fangyi Rao
* Radek Biernacki
Altera: * David Banas
Julia Liu
Hazlina Ramly
Andrew Joy Consulting: Andy Joy
ANSYS: Samuel Mertens
* Dan Dvorscak
* Curtis Clark
Steve Pytel
Luis Armenta
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
Feras Al-Hawari
Brad Brim
Kumar Keshavan
Ken Willis
Cavium Networks: Johann Nittmann
Celsionix: Kellee Crisafulli
Cisco Systems: Ashwin Vasudevan
Syed Huq
Ericsson: Anders Ekholm
IBM: Greg Edlund
Intel: * Michael Mirmak
Maxim Integrated Products: Mahbubul Bari
Hassan Raghat
Ron Olisar
Mentor Graphics: John Angulo
Zhen Mu
* Arpad Muranyi
Vladimir Dmitriev-Zdorov
Micron Technology: Randy Wolff
Justin Butterfield
NetLogic Microsystems: Ryan Couts
Nokia-Siemens Networks: Eckhard Lenski
QLogic Corp. James Zhou
SiSoft: * Walter Katz
* Todd Westerhoff
Doug Burns
* Mike LaBonte
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
Ray Anderson
The meeting was led by Arpad Muranyi
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Opens:
- Arpad: I may not make it next week
- Someone else could run the meeting
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Walter write new BIRD 122 replacement draft
- Done
- Ambrish email reflector regarding BIRD 147 status
- Ambrish: There is confusion over this, but working on it
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New Discussion:
Interconnect Task Group report:
- There was no meeting
Arpad: Walter will introduce a new BIRD proposal and immediately table it
- Arpad showed new BIRD draft "Support PAM4 in AMI Modeling"
- Walter:
- Mainly PAM4 has 4 signal levels
- NRZ is also known as PAM2, but that is not commonly used
- We should only have to tell the tool it is PAM4
- Arpad: PAM can have various signal level counts, could we just have a number?
- Walter: That is possible
- Arpad: Should this be in IBIS, not AMI?
- Walter: [Model] is very much dedicated to binary buffers
- Arpad: Should analog models be in IBIS or in AMI?
- Walter: PAM is tied to SerDes, therefore it should be AMI
- Bob: Should we wait for 802.3bj to be approved?
- Walter: That is well under way, but we can table until then
- Michael M: When will that be finalized?
- Walter: Probably a year
- Arpad: It would be best to spend our time on other BIRDs right now
- Arpad moved to table
- Walter seconded
- No one objected
Arpad showed BIRD draft "AMI Touchstonefile Analog Buffer Models"
- Walter: This uses the Tstonefile AMI parameter to call for an s4p on-die model
- Circuit diagrams show the other elements required for TX and RX
- Last week there was a question about whether we should specify how to
generate the impulse response
- Radek: That was for legacy IBIS
- Walter: We could specify reference methods, not normative
- An alternative would be to use the arithmetic recommended by James
- I do not think either normative or reference methods could be described
- Todd: This is not related to BIRDs 116-188
- Arpad: There were some emails about this
- Immediately after the summit we had a discussion and agreed to have this
proposal
- The other proposal is BIRDs 116-118
- This proposal uses a template and solve the issue only for AMI
- Bob: The proposal did not mention [External Model]
- This seems like it works only with [Model] does not interfere with
[External Model]
- I don't see conflict
- Arpad: At DesignCON I suggested we could have both proposals
- They do not conflict
- Walter said vendors are already doing this and models exist
- Ambrish: Is that good enough?
- Can Walter's proposal be done with BIRDs 116-118?
- Walter: Yes, but a subckt and other unnecessary work is required
- Todd: We wrote the AMI file as though those BIRDs were in effect
- Ambrish: Does this replace BIRDs 116-118?
- Todd: No, we wrote it as though that ISS subckt existed, and just used the
parameters
- There may be a disconnect because this is differential and [Model] is
single ended
- Arpad: There is mention of subckts
- Michael M: Examples would help
- Todd explained this using the circuit diagrams
- Walter: Clarification: the subckt does not include the voltage supplies
- Todd: Once the circuit in IBIS declares parameters they can be used from AMI
- We simply assumed the circuit existed
- Walter: We could wait for BIRD 116 to be approved, then add in the other stuff
- That would be IBIS 6.0 compliant
- Meanwhile we can do it this way and there is no illegal syntax
- Radek: We do not necessarily want it, but the parameters could become reserved
- That would take precedence over the legacy IBIS model
- Ambrish: That would be mandating BIRD 122
- Todd: I agree with Radek, these parameters technically should be reserved
- Arpad: After BIRDs 116-118 are approved we might be required to have the
actual circuits
- Bob: Bypassing BIRDs 116-188 makes sense
- Radek: It is also necessary that we cover how source impedances are treated
- Ambrish: That can be done with the circuits
- Radek: This shortcut is useful
- Todd: We all agreed to have this proposal
- This is not to undermine BIRD 116
- Ambrish: We have gone from model specific to reserved, to just for discussion,
to a real BIRD
- Walter: We can have both solutions
- This does not preclude BIRD 116
- The only question is whether to support the shortcut
- David: Walter said non-straight-line IV curves could not be used
- Walter: They can be used but there will be accuracy problems
- David: Do BIRDs 116-188 allow those non-straight-line features?
- Walter: Since IBIS-ISS is LTI, we will not have that problem
- Todd: You can't model non-linear with it
- Walter: With the AMS languages and SPICE you can
- Arpad: For this we would want reserved, for BIRDs 116-118 model specific
- Other than that they are identical
- I don't mind this interim solution
- There are a few details we would have to go over
- An analog simulator can't have zero time edges, etc.
- Todd: The time is "practically zero"
- David: Something is wrong if touchstone depends on how it is driven
- Todd: The output changes
- Driving with a square wave then a ramp will have different outputs
- David: Is "close to zero" ramp the right approach?
- Todd: It is the best we have right now
- Walter: Impulse responses are all die to die s4ps, that is how they are
doing it?
- Bob: We can:
- Accept this
- Accept BIRDs 116-118
- Accept both
- Arpad: The other BIRDs could also be modified to include this
- Bob: The diff circuit might not be centered around zero
- Only BIRDs 116-118 are general enough for that
- Walter: IBIS-ISS would not handle that either
- IBIS-BSS could do non-LTI
- BIRD 116 should wait for that
- Arpad: That would be an interim solution
- Ambrish: In what order should we discuss these?
- Radek: We should discuss both approaches
- Arpad: We should try adding the shortcut idea to BIRD 116
- Radek: There was a BIRD to add Touchstone as a language
- But that would require specifying the termination conditions
- There is nothing to be done here
- Bob: The press release referred to BIRDs 116-118 as though they are supported
- Are those supported yet?
- Radek: No, but there would be no difficulty doing that
AR: Arpad try to add shortcut language to his BIRDs
Bob: About the PAM4 BIRD, Range would allow it to support any number of levels
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Next meeting: 19 Feb 2013 12:00pm PT
Next agenda:
1) Task list item discussions
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
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