Minutes from the 19 May 2015 ibis-atm meeting are attached. The
following document presented during the meeting has been posted to the
work archive:
*DATE* AUTHOR
<http://www.eda.org/ibis/macromodel_wip/archive-author.html>
ORGANIZATION <http://www.eda.org/ibis/macromodel_wip/archive-org.html>
TITLE <http://www.eda.org/ibis/macromodel_wip/archive-title.html> FORMATS
19-MAY-2015 Walter Katz SiSoft Terminal Names in IBIS (zip
<http://www.eda.org/ibis/macromodel_wip/archive/20150519/walterkatz/Terminal_Names_in_IBIS.zip>)(PDF
<http://www.eda.org/ibis/macromodel_wip/archive/20150519/walterkatz/Terminal%20Names%20in%20IBIS/TerminalNamesInIBIS.PDF>)
Mike
IBIS Macromodel Task Group
Meeting date: 19 May 2015
Members (asterisk for those attending):
ANSYS: * Dan Dvorscak
* Curtis Clark
Avago (LSI) Xingdong Dai
* Bob Miller
Cadence Design Systems: Ambrish Varma
Brad Brim
Kumar Keshavan
Ken Willis
eASIC * David Banas
Marc Kowalski
Ericsson: Anders Ekholm
IBM Steve Parker
Intel: * Michael Mirmak
Keysight Technologies: * Fangyi Rao
* Radek Biernacki
* Nicholas Tzou
Maxim Integrated Products: Hassan Rafat
Mentor Graphics: * John Angulo
* Arpad Muranyi
Micron Technology: Randy Wolff
Justin Butterfield
QLogic Corp. James Zhou
Andy Joy
SiSoft: * Walter Katz
Todd Westerhoff
* Mike LaBonte
Synopsys Rita Horner
Teraspeed Consulting Group: Scott McMorrow
Teraspeed Labs: * Bob Ross
TI: Alfred Chong
(Note: Agilent has changed to Keysight)
The meeting was led by Arpad Muranyi.
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Opens:
- Arpad: Should we discuss [Initial Delay]?
- Michael M: Not yet, there will be a BIRD.
- Radek: We tabled [Define Package Model] but could discuss the changes made.
- What are the differences between the one we approved and what Open Forum
will vote on?
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Call for patent disclosure:
- None
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Review of ARs:
- Arpad to review IBIS specification for min max issues.
- In progress.
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New Discussion:
Directionality BIRD draft
- Michael M: Have all issues been resolved?
- Bob M: I had asked some questions but they may be academic.
- The problem we are trying to solve is not clear.
- Arpad: AMI models do not say if they are TX or RX.
- There is no way to check if they are assigned incorrectly.
- Michael M: It's not much of an issue if they work only in one direction.
- AMI parameters can be used to check them in that case.
- But AMI can be used for bidirectional DDR4 signals, for example.
- Bob M: A bidirectional SerDes that does turnaround makes no sense.
- Michael M: Only the current state would be given, no dynamic turnaround.
- Bob M: In EDA tools I assign models explicitly to TX or RX.
- A single executable that can be TX or RX should be possible.
- Michael M: Users don't want to copy a topology just to model the reverse
direction.
- The BIRD supports single executables, but separate AMI files are required.
- Walter: IBIS describes parts and must describe the behavior of each pin.
- If a pin is I/O then IBIS must be able to describe both behaviors.
- Arpad: We were going to check direction by Reserved_Parameters.
- There are few required parameters, we may not have enough for checking.
- Walter: The model writer can add an In Model_Specific parameter that the
model checks.
- John: A Reserved_parameter would not require that kind of user intervention.
- Arpad: We could require a Reserved_Parameter for model direction.
- Walter: We would define TX AMI files and RX AMI files.
- Radek: A Model_Specific parameter would clarify this.
- Walter: It would be of type Value.
- Bob R: For I/O models it's unclear.
- Walter: There are separate AMI files.
- John: Each model would look for a parameter of a certain name.
- Bob R: The EDA tool doesn't need to know it, only the model.
- Arpad: Is this BIRD ready for submission?
- Bob R: We left the Reserved_Parameters in it.
- Walter: Michael M should issue a clean final draft and we can vote on it next
week.
- Bob R: How would we identify the TX and RX Executable lines?
- Radek: There is a parameter for that in the IBIS file.
- Michael M showed the BIRD.
- Michael M: It is a subparameter of the [Algorithmic Model] keyword.
- There are no Reserved_Parameters defined in the BIRD at all.
- There is however a table listing known TX and RX Reserved_Parameters.
- David: How do we use one DLL for I and O?
- Michael M: It is called from one [Algorithmic Model] with Direction TX and
one with Direction RX.
- Bob R: Can a single DLL be used for multiple models?
- Radek: We removed that restriction.
- Michael M showed the removed phrase.
- Michael M: This was done so existing models don't have to change much.
- Direction is not required except for I/O Model_types.
- David: Can there be multiple Directions in one section?
- Walter: There could be Executable_TX and Executable_RX instead of the
Direction subparameter.
- David: A field right on the line would be consistent with information.
- Arpad: We still need to resolve if multiple TXs and RXs are allowed for one
[Algorithmic Model].
- Walter: We already do, for platforms.
- Bob R: Only one Direction subparameter should be in one [Algorithmic Model].
- John: There could be a risk with having multiple [Algorithmic Model] sections.
- Michael M: Each [Algorithmic Model] should point to one AMI file.
- Doing it this way we can check for that.
- Cadence liked this syntax better.
- Arpad: Can we have two [Algorithmic Model] section with the same Direction?
- David: Could there be subparameter hierarchy?
- Michael M: I don't think we have any examples of that so far.
- Arpad: We have hierarchical keywords.
- Mike L: This will require one AMI file per [Algorithmic Model] block?
- We have not had that rule so far.
- Michael M: Yes.
- Mike L: I know of no models that use different AMI files so far.
- Software would be easier to write with this assumption.
- Bob R: The example in this BIRD has different AMI file names for TX and RX.
- It's not clear.
- David: It's clear, the question is what we want.
- Mike L: Some models have platform dependent Supporting_Files.
- They might want to use separate AMI files for each platform.
- David: So there have to be unique TX and RX AMI files, but there could be
more than two files.
- Radek: Do we currently disallow multiple [Algorithmic Model] keywords?
- Michael M: Yes, that changes in this BIRD.
AR: Michael M email list to start discussion of new Directionality issues.
Problems with Global Ground in IBIS:
- Arpad: We only have time for a short introduction.
- Walter showed a presentation "Terminal Names in IBIS".
- Walter: There is confusion over what a terminal name is.
- It is about voltage references.
- C_comp is involved.
- Some of our figures have ground symbols.
- We made an editorial error while going from IBIS 5.0 to 5.1.
- We should replace some terminal names in diagrams with standard names like
A_pcref.
- The references for IV curves must be discussed, some use a mythical ground.
- It would be best to use C_comp_power_clamp and C_comp_ground_clamp instead
of C_comp.
- Arpad: Will this be discussed in the interconn meeting tomorrow?
- Walter: It should be.
AR: Walter send "Terminal Names in IBIS" presentation to Mike L for posting.
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Next meeting: 26 May 2015 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
