[ibis-macro] Minutes from the 19 Mar 2013 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 19 Mar 2013 16:29:15 -0400
Minutes from the 19 Mar 2013 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 19 Mar 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:
- Walter: Would like to discuss BIRD adoption plan for IBIS 6.0
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Walter write new BIRD for repeater/retimer pin keywords
- In progress
- Arpad try to apply BIRD 158 shortcut language to his BIRDs 116-118
- In progress
-------------
New Discussion:
Analog BIRDs:
- Arpad showed a list of BIRDs that have been converted to the new BIRD format
- Arpad: The content has not changed.
- This may be easier once my AR has been done
- Arpad showed presentation "Analog BIRD Overview":
- slide 3:
- Arpad: The first four BIRDs would have to be voted in to implement the
approach
- The other two are optional.
- Arpad: A BIRD-like document has been uploaded but not yet announced
- This combines four BIRDs
- We should read it
- It could be submitted as an official BIRD if that helps
- Ambrish motioned to submit the combined BIRD incorporating BIRDs
116,117,118,129
- Bob seconded
- There were no objections
- Bob: We should look at them first
- I have some technical comments, one about parameters and the other about
parsing logic
- Arpad: We can have those discussions next week
Arpad showed presentation BIRD 159 Discussion:
- slide 2:
- Arpad: There was a question about the receiver threshold voltage
- Mike Steinberger and Walter had replied about this
- The IBIS specification has clear language
- Walter: We should decide that the waveform is centered around 0V
- Michael M: What is the reference location?
- Arpad: Let's get to questions at the end
- slide 3:
- Arpad: The specification says there is a single waveform
- It does not assume it is differential
- slide 4:
- Arpad: On page 123 the interface is said to be differential
- slide 5:
- Arpad: How do we resolve this?
- Michael M: Any common mode effect is outside the scope of AMI
- Walter: Agree
- Michael M: Most flows are statistical
- It still needs to be known if the common mode bias is correct
- AMI models are not helpful for that
- David: So a DC bias will not be modeled correctly?
- Todd: We are only saying the network characterization produces a
differential waveform
- Nothing is said about common mode
- Walter: The impulse response is based on the differential output
- This uses the TX analog model
- David: The channel has even and odd mode propagation
- The RX input will never know about common mode
- The question is if the differential behavior of the TX can be affected
- Arpad: We pass to the algorithmic model an impulse response, not a waveform
- Ambrish: GetWave receives a waveform
- Arpad: It says "centered nominally around zero volts"
- Walter: A stream of ones will not be centered around zero
- We transmit only the differential part of the waveform
- Todd: David was asking if the mode conversions affect the differential
waveform
- David: Michael asked if loading that is not nominal changes the result
- Can that happen with a Ramp-only TX?
- Todd: Yes
- Arpad: It can if the differential buffer uses two different models
- Todd: Non-linear curves can create those effects
- David: So Ramp-only models do not preclude us from catching those effects
- Walter: Edge timing skews can cause this effect too
- EDA tools with proper analog models will model it
- Arpad: The algorithmic model will not care about non-differential effects
- I thought we were supporting both single ended and differential models
- Walter: I could create an S2P just to represent the differential part of a
channel
- The intent was not to do single ended DDR4
- AMI does not really support it
- Arpad: Are we restricting ourselves unnecessarily?
- Walter: We can fix it in the future if the need arises
- At that point an RX receiver threshold fix would be needed
- Todd: The specification we have now is about differential
- Arpad: What about the page 123 language?
- Radek: That should be eliminated
- David: The model only knows it is receiving a series of numbers
- Todd: It won't be right if the channel has not been handled correctly
- Walter: I think the answer to "Is it clear to everyone" is no
- This BIRD proposal should be withdrawn
- Bob: The assumption of centering on 0V is still a problem
- Walter moved to recommend voting down BIRD 159
- David seconded
- No one objected
- David: Does Michael have any thoughts about his questions?
- Michael M: Statistical analysis does not account for common mode
- That's OK, but it needs to be clearly documented
Walter: We should discuss a BIRD plan in a future meeting
- Michael M: Agree, we have 18 or 19 open BIRDs now
- Members should submit their preferred lists
- Michael M: Speaking as an Intel employee for a moment, a repeater
specification
is very important
- Walter: I will send a spreadsheet
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Next meeting: 26 Mar 2013 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
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