IBIS Macromodel Task Group

Meeting date: 3 December 2019

Members (asterisk for those attending):
ANSYS:                        Dan Dvorscak
                              Curtis Clark
Cadence Design Systems:       Ambrish Varma
                              Ken Willis
                              Kumar Keshavan
Intel:                        Michael Mirmak
Keysight Technologies:        Fangyi Rao
                            * Radek Biernacki
                              Ming Yan
                              Todd Bermensolo
Mentor, A Siemens Business: * Arpad Muranyi
Micron Technology:          * Randy Wolff
                            * Justin Butterfield
SiSoft (Mathworks):         * Walter Katz
                            * Mike LaBonte
SPISim:                     * Wei-hsing Huang
Teraspeed Labs:             * Bob Ross

The meeting was led by Arpad Muranyi.  Justin Butterfield took the minutes.

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Opens:

- Upcoming meeting schedule:
  - Arpad proposed to cancel the meetings on December 24 and 31 for the Holidays and 
    on January 28 for DesignCon.

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Review of ARs:

- Randy and Michael M. to invite DDR memory and controller vendors to comment
  on new protocols.
  - In progress.
  
- Bob to update BIRD197.6_draft_3 based on the discussion in the meeting last week.
  - Arpad reported this was done.

  
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Call for patent disclosure:

- None.

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Review of Meeting Minutes:

Arpad suggested to review the minutes next week to give more time to review.


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New Discussion:

Arpad reviewed that two weeks ago we planned a vote on the subject of enabling Back 
Channel Interface in statistical mode.

List of options to choose from in the vote:
1.	AMI_Impulse
2.	AMI_Init
3.	AMI_GetWave

Arpad shared an email from Ambrish, which voted for item number 1.  Arpad suggested 
we could eliminate item number 3, since Cadence had asked for this.  Walter agreed 
with this.  Arpad narrowed the list to options 1 and 2.

Walter noted he strongly recommends AMI_Impluse, since AMI_Init will require a lot of 
work to change the IBIS specification.  Randy asked about the difference between the 
two approaches and how the memory is handled.  Walter responded, if you use 
AMI_Impulse, all the Tx has to do is write a BCI out string, which gets passed to the 
Rx model.  The model only has to parse this BCI string.  If we use the AMI_Init, we 
have to change how the branch is output.  And, the Rx model will have to parse the 
entire AMI parameters.  In terms of simulation efficiency, there would not be much 
difference between AMI_Impluse and AMI_Init.

Walter made a motion to vote on the options for enabling Back Channel Interface in 
statistical.  Randy seconded the motion.  There were no objections.

The roll call vote tally was:
Cadence - Option 1.
Mentor - Option 1.
Micron - Option 1. 
SiSoft - Option 1.
SPISim - Option 1.
Teraspeed Labs - Option 1.

The roll call vote concluded with a vote tally of Option 1. – 6, Option 2. – 0, 
Abstain – 0.  Option 1. was selected as the path forward.

Walter took an AR to draft a BIRD on based on the AMI_Impulse approach for this group 
to review.


BIRD197.6_draft3:
Arpad asked Bob to review the changes to BIRD197.6_draft3.  Bob had made changes to 
reflect the discussion from the last meeting.  Arpad asked about the sentence Michael 
had added, but he had later requested to be removed.  Bob stated he had not captured 
this change.  Arpad noted the latest email from Michael stated he wanted to withdraw 
his requested additional text.  Bob stated it is unclear which text this applies to.  
Walter noted at the beginning of the email the text was requested, so the comment to 
withdraw the sentence was in this context.  Walter suggested to delete the sentence: 
"This shall include, but is not limited to, channel effects as well as the impact of 
any equalization imposed by the transmitter." from the BIRD draft.  Bob removed this 
sentence and saved the document as draft4 of BIRD197.6.

Arpad asked if there was any further discussion on BIDR197.6.  Walter suggested to 
post this and plan to review and vote to submit the BIRD to the IBIS Open Forum.  Bob 
suggested to vote on it today.

Walter moved to submit BIRD197.6 to the IBIS Open Forum.  Randy seconded the motion.  
There were no objections.

Bob took an AR to submit BIRD197.6 to the IBIS Open Forum.  Arpad suggested to change 
the red text to black text.  Mike suggested the revision markup should show the 
difference from the previous version (BIDR197.5), but Randy could do this if he 
chooses.


BIRD181.2:
Mike suggested to give a brief review of the BIRD.  BIRD181.2 is on the topic of IV 
curve clarifications.  Mike noted BIRD181.2 is a draft, where he started with IBIS 
7.0 as the basis.  He mentioned changes of "pin" to "terminal" and other consistency 
changes.  The BIRD now covers three sections.  The first change uses a spice like 
notation to express the names of the terminals that the voltage is measured across 
for [Pulldown], [Pullup], [GND Clamp], and [POWER Clamp].  Arpad asked if there were 
technical changes in BIRD181.2.  Mike replied this is a clarification BIRD to clean 
up the language.  The second change is to the [ISSO PD] and [ISSO PU] keywords to use 
the same spice like notation.  The third change is to V(g,s) from Vgs, where the 'g' 
and 's' nodes are previously defined in the IBIS specification.  The fourth change is 
also to V(g,s), but in a different section.

Mike noted he may need additional changes from "pin" to "terminal" as Walter had 
suggested.  He will need to take care of making this change.

Arpad asked about the terms "pins" vs. "pads" and if we would need some changes for 
these, but this could be a separate effort.  Mike agreed this would be a separate 
effort in new BIRD.

Walter asked if we can submit a version that makes these changes to IBIS 7.0.  Mike 
replied he could use markup on the IBIS 7.0 text with these changes.  Arpad agreed 
this could be useful in this case.

Mike took an AR to make the changes as noted to BIRD181.2 and send it out.


- Walter: Motion to adjourn.
- Randy: Second.
- Arpad: Thank you all for joining.


AR: Walter to draft a BIRD on based on the AMI_Impulse approach.
AR: Bob to submit BIRD197.6 to the IBIS Open Forum.
AR: Mike to make the changes as noted to BIRD181.2 and send it out.

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Next meeting: 10 December 2019 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
