[ibis-macro] Minutes from the 31 Jul 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Wed, 1 Aug 2012 08:37:19 -0400
Minutes from the 31 Jul 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 31 July 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
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
LSI Logic: Wenyi Jin
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
-------------
Review of ARs:
- Arpad: There was an AR from last week for me to create a bus package model
example
using BIRD 125
- Will be addressed in presentation today
- Bob to propose a simpler way for addressing the needs of parameter passing
under [External Model] and [External Circuit]
- not done
-------------
New Discussion:
Arpad showed a presentation "Package Modeling in IBIS":
- slide 2:
- Arpad: Colored terms indicate new syntax
- Michael M: You have to use node declarations?
- Arpad: You don't have to, they are just for the extra, explicit nodes.
- James: What if there are more die nodes than pins?
- Arpad: A later slide covers that
- IBIS assumes implicit pad names based on pin names
- Explicit names are needed when there is not one-to-one mapping
- This syntax overrides implicit names only as needed
- Michael M: That may be a major discussion topic
- slide 5:
- Arpad: This shows two die pad nodes connected to pin 2
- Also two pins are connected to die pad_4
- slide 6:
- Arpad: We did not originally define in IBIS how to connect power
- Buffers are instantiated by column 3 of [Pin], so there can be only one
- slide 9:
- Arpad: We would need cascaded circuits here
- slide 10:
- Arpad: BIRD 145 proposes cascading models to solve the problem
- We have to provide names for the buffer terminals
- slide 11:
- Arpad: This shows both BIRD 125 and 145
- This should answer some of the email questions
- In BIRD 145 [Model Call] instantiates buffers
- The legacy IBIS keywords match ports by pin name
- The IBIS-ISS subckt call matches by position
- In the [Circuit Call] portion ports are connected to [Node Declaration]s
- Michael M: The objective is to make optimum use of existing package
keywords?
- Arpad: Yes, we should minimize changes
- Michael M: For tool vendor minimal changes are good
- Model makers might be in a different position
- Almost no one uses [Define Package Model], so they would have to learn it
from scratch
- Arpad: Is [Define Package Model] unused because the syntax is so bad?
- Michael M: Electrically long packages are hard to model with IBIS
- The syntax is constraining
- Swathing is not easy either
- slide 12:
- Arpad: This shows that arbitrary interconnections are possible
- You can't connect two pins to one package port though
- slide 13:
- Arpad: This explains the previous limitation
- There can be only one port number per pin
- slide 14:
- Arpad: Red and blue lines show power and ground connections
- slide 16:
- Arpad: A limitation here is the assumption of fixed pad topology
- slides 18-24:
- Arpad: These show a model sliding up and down the pin map
- slide 25:
- Arpad: This shows the syntax that does the sliding
- We call port_map names instead of node names
- Pins are assigned to nodes positionally
- It works somewhat like [Model Selector]
- The Position parameter selects which mapping to use
- Parameter trees with dependency tables could be synchronized with the
Position
- Radek: Is there a continuation character if pin or node lists become long?
- Arpad: The words "pins" and "nodes" indicate what is on the rest of the line
- There could be more than one of each
- That could be refined
- Radek: Ports have two terminals, it would be best not to use that term for
this
- James: On slide 18 what is the difference between [Pin] and [Pin Numbers]?
- Arpad: [Pin Numbers] is in the package and it has to repeat what is in [Pin]
- James: How can slide 12 show a one-to-many relationship?
- Arpad: The IBIS spec may allow a subset, which would allow this
- If not we can change the specification
- James: But is connecting one to many possible?
- Arpad: That may have been a mistake
- RAMBUS had a pad connected to two pins
- James: It could be done inside the IBIS-ISS subckt
Arpad: We could go through Walter's presentation:
- Walter: There is not enough time now
- Michael M: Will there be other IC vendor presentations?
- Ray: One of the proposals submitted so far should be good enough
- Randy: Agree with Ray, we should go over Walter's presentation
- Arpad: My proposal does not include X/Y coordinates
- Someone could propose something along that line
- Walter: Are there any models using [Circuit Call] and other keywords together?
- Arpad: Probably not, but there are a few [Define Package Model]
- Ray: We have delivered hundreds of [Define Package Model] with RLC matrices
- That format is running out of gas
- Michael M: Anders might check the model library
- James: It would help to have a real IBIS file example
- Walter: Example models based on my example cases would be good
AR: Arpad prepare example BIRD 125 IBIS file set
-------------
Next meeting: 07 Aug 2012 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
Other related posts:
- » [ibis-macro] Minutes from the 31 Jul 2012 ibis-atm meeting - Mike LaBonte
