[ibis-macro] Minutes from the 7 Jan 2014 ibis-atm meeting

  • From: Mike LaBonte <mike@xxxxxxxxxxx>
  • To: ibis-macro@xxxxxxxxxxxxx
  • Date: Tue, 07 Jan 2014 16:20:25 -0500

Minutes from the 7 Jan 2014 ibis-atm meeting are attached.

IBIS Macromodel Task Group

Meeting date: 17 December 2013

Members (asterisk for those attending):
Agilent:                    * Fangyi Rao
                            * Radek Biernacki
Altera:                       David Banas
                              Julia Liu
                              Hazlina Ramly
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 Rafat
                              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
                            * Andy Joy
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


- Arpad: We will have no meeting Jan 28, conflicts with DesignCon

Call for patent disclosure:

- None

Review of ARs:

New Discussion:

EBD/EMD/interconnect direction:
- Walter showed a presentation "IBIS-ISS Package Proposal Status"
- slide 5:
  - Walter: We decided to support sNp models directly.
    - We need rules for a few "maybes".
- slide 15:
  - Walter: We need to support sparse ports.
- slide 17:
  - Walter: This will be presented at the upcoming summit.
    - This slide had been dropped but would like to discuss it there.
  - Bob: What does model type mean here?
  - Walter: It is about associating package models by [Model] Model_type
- slide 20:
  - Walter: We may want distinct Delay_Corner and Xtalk_Corner.
- slide 24:
  - Walter: I would like to resolve the first question here today.
    - We have not yet debated the actual proposed syntax.
    - The EMD syntax should be similar to package model syntax.

- Bob: On slide 7 Keywords and Sub-Params are mixed up
- Walter: Some editorial work is needed.

- Bob: On slide 24 Model_name means [Model] name?
- Walter: Yes
- Bob: How to identify different signal paths with same model name?
- Walter: There can be no joins, so they remain unique
- Bob: How is a package model chosen when it might match multiple rules?
- Walter: There are precedence rules.
- Radek: This tries to save space in the file by introducing complicated rules.
  - That may not be a good idea.
  - Specifying each pin will not take that much space.
- Walter: A package with 500 pins would need 500 entries.
  - These concepts have been requested by users.
- Radek: Association by IBIS buffer model is good.
  - We still need to solve the problem of unused ports with coupled models.
- John: Do we ever have 500 package paths that should be modeled the same?
  - Or will there be a variety?
- Walter: Yes, either
  - We have had to bench measure packages to get all of the connection lengths.
- John: There can be a problem of identifying victims but not distinguishing 
- Walter: An s1000p can be used to do anything.
  - The crosstalk impact must be bounded to be practical.
  - This usually results in s12p models
  - Vendors are gaining technology to generate detailed models.
- John: Touchstone2 sparse format would help
- Walter: IC vendors don't want to generate those
  - They want a standard that sets a crosstalk limit, and that becomes the 
  - We implement those bounded models in our tools, differently
  - Vendors would like to specify those directly

- Walter: Can we decide that there will be direct Touchstone models?
- Radek: It needs to be specified carefully.
- Walter: We may fail, but I think we have decided to try.

- Walter discussed slide 22, Unconnected Port Naming Rules.
- Fangyi: Conventionally, any unconnected port is open.
  - The EDA tool doesn't have to do anything, the user will connect those nodes.
- Walter: With 500 ports most will require some termination.
- Fangyi: The EDA tool should handle that, not the model.
- Radek: Then there will be different solutions in different tools.
  - We are trying to specify more of the netlist, outside of IBIS-ISS.
- Walter: Vendors want to create 500 port models, knowing they will rarely all 
be used.
- Fangyi: Tools can give users a selection of terminations.
- Arpad: The model maker has an idea of what should be used.
- Walter: There should be an override.
- Fangyi: Agree, the user must have final control.
- Walter: Yes, but a default should be given.
- Arpad: We might want an option to use the Touchstone reference impedance.
- Walter: That option is there, when R=0.
- Fangyi: That is not a good idea.

- Bob: On slide 20s, "p" and "n" would be better than "+" and "-".

- Walter: I will ask for at least an hour to discuss this at the summit.

AR: Walter send presentation to Mike for posting

Next meeting: 14 January 2013 12:00pm PT

IBIS Interconnect SPICE Wish List:

1) Simulator directives

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