[ibis-macro] Minutes from the 3 & 24 Jan 2012 ibis-atm meetings
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Sun, 5 Feb 2012 20:22:57 -0500
Minutes from the 3 & 24 Jan 2012 ibis-atm meetings are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 24 Jan 2011
Members (asterisk for those attending):
Agilent: * Fangyi Rao
* Radek Biernacki
Altera: * David Banas
Ansys: Samuel Mertens
Dan Dvorscak
* Curtis Clark
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
* Feras Al-Hawari
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
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
The meeting was lead by Arpad Muranyi
------------------------------------------------------------------------
Opens:
- Arpad: Minutes from last week will be sent to Mike for posting
- Arpad: There will be no meeting next week due to DesignCON
- Arpad: Can we remove the last agenda item?
- Walter: Yes it can be removed
--------------------------
Call for patent disclosure:
- None
-------------
Review of ARs:
- None (may find some after review of minutes from last week)
-------------
New Discussion:
IBIS 5.1 parser plans:
- Bob: The editorial committee has been discussing this
- Use_Init_Output is deprecated
- Not going to document executable model flow changes in 5.1
- 5.1 rules will apply to 5.0 models
- 5.0 models can have the relaxed syntax allowed in 5.1
- We can discuss this at the DesignCON summit
- Arpad: If Version is absent 5.0 rules will apply?
- Maybe it should default to 5.1
- Bob: A BIRD would be needed for that
- BIRD 126 already covers this well
- It mostly deprecates 5.0, with exceptions
- Arpad: I like the idea but if 5.0 rules are not used we should not default to
5.0
- Radek: It is not 100% clear what to do if Use_Init_Output is present
- Walter: If AMI_Version is 5.1 Use_Init_Output will be flagged as an error
- In most cases we can add AMI_Version and delete Use_Init_Output
Walter showed an email about Analog Buffer Modeling:
- Walter: No one has objected to these statements
Walter showed another email with conclusions:
- Walter: Point 2 is not 100% true
- With just [Ramp] the V-T can't be represented
- External Model could have a D-A with a PWL to give the K(t) function
- This will represent the behavior of any LTI driver
- Walter: Point 4 is about it being easy to accurately describe analog behavior
- Every swing setting has a different Voh and impedance
- An IBIS file can be generated with many [Model Selector]s, many AMI files
- Simulators often do quadratic rounding of ramp corners
- Would like to have four internal reference models with reserved subckts
- Feras: We don't need the new keywords
- IBIS-ISS subckts can model it
- Walter: The reference subckt names are not new keywords
- Arpad: Is this about standard ISS files or hardcoded circuits?
- Feras: You proposed 4 keywords in an email
- Walter showed a previous email
- Walter: We can ignore the Reserved_Model keyword
- I would only like these subcircuit names and files to be reserved
- They would not have to be supplied with each model
- Feras: Would it be inserted in the IBIS file, not external?
- We should be able to include an analog model with or without AMI
- Walter: The BIRD allows that
- Arpad: BIRD 118 can be extended for this purpose
- Ambrish: It should allow linking just any file to the AMI section of IBIS
- Walter: Adge Hawes will have related presentation at DesignCON
- It will show what vendors need
- Arpad: If we allow just any file we have to spell out the allowed syntax
- Those changes can be made though
- Feras: You have to have an AMI model present
- The [Algorithmic Model] section should not be required
- Walter: It's OK if this is used only where AMI is present
- Ambrish: How would we handle it when there is no AMI?
- Arpad: We could have a file pointer without relying on the AMI keyword
- Feras: Users must be able to use models with or without DLLs
- Walter: There will be a presentation about a model with 128 Touchstone files
in it
- Arpad: We just need a keyword other than AMIfile
- The file format is tree format just like AMI though
- Kumar: AMI does not own the tree format
- Walters: We should listen to what IC vendors want
- Ambrish: How would corners be chosen?
- Arpad: The GUI will have to let users choose
- Walter: It could be done as an Include statement
- Radek: So this is not a reserved parameter, but a reserved name
- Walter: One problem is having two different models with the same name
- There will be only one of each of these reserved models, no collisions
- Ambrish: That is for the user and vendors to deal with, not the spec
- If it's hardcoded in the tool we can't change it
- Walter: Then a file can be created for anything new
- Fangyi: Why are there 4 reserved file names?
- Feras: We can publish templates and those can be copied
- How will the user find the actual subcircuit?
- Walter: It would be in the spec
- It would also be supplied as files
- Tools might handle it efficiently through internal means
- Fangyi: Why can't vendors use a different file name?
- Walter: Then we will have file management problem
- Feras: There are many other circuit types needed
- Walter: Nothing prevents them from doing that
- Ambrish: Templates that only work for AMI defeat the purpose
- Walter: IBIS-ISS was created for AMI analog models and interconnect
- The only application right now is AMI, until we have BSS
- Arpad: The 6 points are all correct
- Why do we need a shorthand for these circuits?
- Walter: At this point I only want them as reference circuits
- Radek: A circuit file with no reserved name causes no problem
- Walter: I have a model that has 260,000 combinations
- Arpad: What benefits do the 4 circuit bring us?
- Walter: They cover all known SerDes standards and contemplated for 4 years
- Arpad: We can just supply the files
- Kumar: These circuit models are an approximation
- The parameters are not cast in stone
- Fangyi: Why do we still need Touchstone if these are accurate?
- Walter: That is needed for broadband
- Complicated subckts would be needed, but they are proprietary
- Fangyi: So these do not cover everything
- Feras: What if someone wants non-linear models?
- Walter: ISS only allows linear
- Feras: [External Model] allows other non-linear languages
- Walter: I have not seen a channel where a non-LTI model makes a difference
- Industry tools all use LTI models like MatLab, HSS-CDR
- Kumar: We can't restrict ourselves to what those tools do
- Fangyi: This analog model is not just for AMI
- Rambus did experiments showing that
- Kumar: We can't assume superposition will apply into the future
- Walter: LTI is more true as speeds go higher
- Fangyi: Can parameter names be changed for the reserved models?
- Walter: No
- Ambrish: That makes them reserved parameters
- Walter: Not by the AMI definition
- They could be called pseudo-reserved
- We need to remember that there are 3 groups: users, EDA vendors, IC vendors
- Ambrish: The IC vendors tend to not be well versed in these issues
Meeting ended.
-------------
Next meeting: 7 Feb 2011 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
IBIS Macromodel Task Group
Meeting date: 03 Jan 2012
Members (asterisk for those attending):
Agilent: Fangyi Rao
Radek Biernacki
Altera: * David Banas
Ansys: Samuel Mertens
* Dan Dvorscak
* Curtis Clark
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
Feras Al-Hawari
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
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
The meeting was lead by Arpad Muranyi
------------------------------------------------------------------------
Opens:
- Arpad: We could cancel the 31 Jan meeting, near the DesignCON summit
--------------------------
Call for patent disclosure:
- None
-------------
Review of ARs:
- Arpad send BIRD 123 changes from today to Walter
- Done
- Walter update BIRD 123 draft
- Done
- Arpad update Usage
- Sent to email list, will be posted
-------------
New Discussion:
Walter showed the Jitter BIRD:
- Ken: I had asked for additional verbage to be added but do not see it
- Walter: I have added it into the BIRD introduction, but not to the IBIS spec
changes
- Ken: It should go in the spec to guide model developers
- Walter moved the paragraphs into the spec change portion
- The editorial group can decide if/where to move those paragraphs
- Arpad and Bob agreed with this change
- Bob: List, Increment and Step types have been added
- Are these types needed for jitter parameters?
- Arpad: It would be useful to use this table for all Reserved parameters
- Bob: We already have 4 tables
- They could be merged but grouped
- Bob: There was a Tx_Sj_Frequency issue, can't find it now
- It was a 5.1 issue
- Walter: Discussions of the changes from old versions to new should be separate
- We repeatedly spend time on this issue
- Bob: Once we have 5.1/5.2 we have no basis for writing a parser
- Arpad: This is a big issue, should be discussed in Open Forum
- What is the problem with writing a parser?
- Bob: The parser has to parse old versions that the new spec will not describe
- Bob motioned to vote to submit BIRD 123 with changes
- Ken seconded
- No objections, the motion passed
AR: Walter submit updated BIRD 123 to Open Forum
Arpad showed the new Usage Out Fix BIRD draft:
- Arpad: I added two small sections
- Page 140:
- The descriptions were misleading
- It now has "to the AMI model"
- Corner type for Usage Out is disallowed
- The model is not the authority to know the selected corner
- In BIRD 127.4
- Default and Value are mutually exclusive, must not be used together
- They are synonyms in this case
- Default is not allowed for Usage Out
- Default is optional for Range, List, Corner, Increment, Steps
- Note 10 is moved to above the list of Notes
- This is an actual rule, not just a note
- Ambrish: We could have an example to show what the EDA tool should do
- Currently it only says what can be ignored
- Arpad added a phrase
- Ambrish: An example would be better
- Bob: The removed note should still be in the notes
- Arpad re-inserted a note #8
- Bob: We do not require Default and Value to be exclusive?
- Walter: There is an implied default for all types but List
- We should recommend using Default only for List
- Arpad: We could eliminate Default by using the first List item as the default
- Mike: Do we specify preference order between Default and implied defaults?
- Arpad: Yes, Default must be used if present
- Bob: There is a question on how Default interacts with Increment
- Walter: This BIRD clarifies all of the ambiguities
- Arpad: We can review one more time before submitting
AR: Arpad send updated Usage Out Fix BIRD to Mike for posting
Arpad showed a slide showing package BIRDs by sponsor:
- Arpad: We should weed out some BIRDs
- Walter: BIRDs 116-118 are a valid way to do it
- BIRD 116 needs a reference to IBIS-BSS to handle non-AMI buffer models
- Arpad: This will be a major topic of discussion in our next meetings
Meeting ended.
-------------
Next meeting: 10 Jan 2011 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
Other related posts:
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