[ibis-macro] Minutes from the 04 Sep 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 4 Sep 2012 16:17:44 -0400
Minutes from the 04 Sep 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 04 Sep 2012
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
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
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
Sigrity: * Brad Brim
Kumar Keshavan
Ken Willis
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
------------------------------------------------------------------------
Opens:
- None
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Greg provide examples to show what IC vendors need
- Done
- Michael M provide examples to show what IC vendors need
- In progress
- Arpad prepare example BIRD 125 IBIS file set
- Done
-------------
New Discussion:
Arpad showed an example IBIS file:
- Arpad: The [Package Model] keyword looks the same
- The [Define Package Model] keyword also looks the same
- The [Pin] keyword calls MODELCALL in the model column, a reserved word
- Comments in [Pin] show {} substitution
- This examples makes no use of [Diff Pin]
- [Node Declarations] give diff pair nodes, both signal and pad
- Port_map parameters within [Model Call] make the node connections
- There are multiple Diff_Signal_pins, but IBIS doesn't allow that yet
- [Circuit Call] makes the package connections
- [External Circuit] is used to connect the on-die model
- Subckts are parameterized
- In [Define Package Model] the [Pin Numbers] keyword is retained
- In [Package Circuit] the connections are made to declared nodes
- The pins and pads are matched positionally even if list lengths do not match
- A parameterized variable is used for RLGCMODEL to make it more flexible
Arpad showed a presentation:
- slide 28:
- Arpad: This shows ports connected to pins
- Also buffer nodes are connected to pad nodes
Back to the example IBIS file:
- Arpad: This makes it possible to have "sliding pins"
- Michael M: This is assigned explicitly to a pair of pins
- This is a simplified swath scheme, but it does not cover cases in between
- Arpad: This is only for a diff pair model
- If there were more it could show coupling
- Michael M: Somehow a subset must be intelligently selected, the user or the
tool
- Arpad: This is more a sliding mechanism than swathing
- No edge effects are involved here
- Michael M: We have to look at where the burden of computation falls
- Does the EDA tool do it or the model maker?
- Arpad: The tool has to do a reduction before we get to this point
- James: That is too restrictive
- It would be better to start from a syntax with no assumptions
- How are model names resolved from the [Pin] table?
- In the RX model there are no node names
- Arpad: The model has implicit legacy analog and digital IO ports
- Using BIRD 145 we can use their predefined names to make the connections in
[Model Call]
- Walter: This shows 3 TX and 3 RX with different lengths
- [Model Call] would need 128 lines to cover the full chip, twice
- [Port Map] would need 256 entries, twice
- The lengths are not swathed, unless a parameter handles that
- It would take quite a bit to represent a fairly standard package
- Arpad: Parameters can handle the length variations
- James: The connection mechanisms are complicated, still not clear to me
- Mike L: A diagram might help
- Arpad: The slide is for that, but it does not have the needed labels
Walter showed "Morphing IBS to EMD and IBISx":
- slide 3:
- Walter: We will show legacy.ibs, incremental.ibs, package.emd and
bare_die.ibsx for a real part
- slide 5:
- Walter: Everything in red is new
- [Tstonefile] is added, same as BIRD 122
- slide 6:
- Walter: This has keywords to call an IBIS-ISS package
- The indentation is for readability, although IBIS might not like it
- slide 7:
- Walter: [Circuit Call] is better than [External Model] for calling
Touchstone
- Touchstone is LTI
- For [Model] we require IBIS-BSS
- Touchstone is all that is needed today for on-die models
- slide 8:
- Walter: We only need one pin list
- Parameters allow us to add other information
- EMD files do not contain silicon, they call silicon models
- slides 9 & 10:
- Walter: In the future EMD could call IBISx
- Extended nets make it easy to connect pins in one to another
- slide 11 & 12:
- Walter: IBISx is completely in parameter tree format
- It could have equation based models too
- slide 13:
- Walter: We should table [External Model] BIRDs
- They might be needed when on-die models beyond Touchstone are needed
- James: Package pad nodes are connected to silicon pads?
- Walter: For silicon the pads appear to be pins
- James: [Extended Nets] is a required keyword?
- Walter: Yes
- The concept is important for power modeling where power pins don't map 1-1
to pads
- Michael M: The number of things modeled is set by the model maker
- There is no swathing
- If the model has an s50p the user has ti figure out how to reduce it
- Walter showed a 12 port example
- The EDA tool should do it transparently
- At least one EDA tool does this
- James: How to designate when crosstalk is desired?
- Walter: Aggressors are marked with A, others are victims
- James: This predetermines the aggressors
- Walter: That is the way vendors are delivering models
- Some vendors may come up different requirements that will need other
keywords
- These have been discussed before and they will come up again
- We really need IC vendors to say what their needs are
Arpad encouraged all to provide feedback and more information.
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Next meeting: 11 Sep 2012 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
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