IBIS Macromodel Task Group

Meeting date: 29 March 2022

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Amazon:                       John Yan
ANSYS:                        Curtis Clark
                            * Wei-hsing Huang
Cadence Design Systems:       Ambrish Varma
                              Jared James
Google:                       Zhiping Yang
Intel:                      * Michael Mirmak
                              Kinger Cai
                              Alaeddin Aydiner
Keysight Technologies:      * Fangyi Rao
                              Majid Ahadi Dolatsara
                              Ming Yan
                              Radek Biernacki
                              Rui Yang
Luminous Computing            David Banas
Marvell                       Steve Parker
Mathworks (SiSoft):         * Walter Katz
                              Mike LaBonte
Micron Technology:          * Randy Wolff
                              Justin Butterfield
Missouri S&T                  Chulsoon Hwang
Siemens EDA (Mentor):       * Arpad Muranyi
Teraspeed Labs:             * Bob Ross
Zuken USA:                  * Lance Wang

The meeting was led by Arpad Muranyi.  Randy Wolff took the minutes.

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Opens:

- None.

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Review of ARs:

- AR: Arpad to send an updated draft 19 of BIRD213.1 to the ATM list.
  - Done.

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Call for patent disclosure:

- None.

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Review of Meeting Minutes:

Arpad asked for any comments or corrections to the minutes of the March 22
meeting.  Randy moved to approve the minutes.  Arpad seconded the motion.
There were no objections.

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New Discussion:

BIRD draft to clarify "root name" definition and usage:
Michael showed draft 4 from March 8.  He changed highlighting to make it 
easier to see exactly the changes from IBIS 7.1. There was a clarification 
from Mike LaBonte describing the root name.  Arpad agreed with movement of one 
sentence as requested in the last review.  There were no other comments.

Michael moved to vote on submitting the BIRD to the Open Forum.  Bob seconded 
the motion.  There were no objections.

BIRD213.1 draft 20, PAMn:
Arpad showed the draft 20 document he started based on Randy’s suggestion at 
the end of the previous meeting to move the symbol_time and clock_times 
related text from pg. 278 to pg. 223 in the existing spec.  Yellow highlights 
showed these changes.

Arpad was not sure how to deal with the sentence ‘For PAM4, the edge threshold 
crossing time is only meaningful for transitions between symbols 0 and 3 and 
between symbols 1 and 2.’ in a general way that would also apply to PAMn.  He 
was also wondering why this statement did not mention transitions between 
symbols 0 and 2 and between symbols 1 and 3.

Fangyi proposed text for the clock_times description on page 229 related to 
PAM4. He thought we should only mention how clock_times is used and not 
mention edge crossing.  His text was related to draft 19 on page 4 in yellow 
highlight.  The text is to be moved to page 223. 

The new text is "The sample times equal clock_times + 1/2 UI + offset, where 
offset is defined by Reserved Parameters PAM_Offset and PAM4_UpperEyeOffset, 
PAM4_CenterEyeOffset and PAM4_LowerEyeOffset."

Arpad showed other page 278 text changes rewritten from draft 19 to flow 
better.  Fangyi suggested an addition of "for PAM4 signaling" to one sentence.  

Arpad noted that we are not providing an equivalent in PAMn for the PAM4 
encoding parameter.  The statement that the usage of the new PAMn parameters 
is highly recommended is an indication that we want to phase out the usage of 
the old PAM4 parameters, but people wanting to define encoding will end up 
having to use the old PAM4 parameters.  Walter thought we could keep the 
PAM4_Mapping along with the new PAMn parameters when n=4.  Randy noted that 
Modulation and Modulation_Levels cannot coexist.  He was not sure if other 
PAM4 keywords could exist if Modulation is missing.

In IBIS 7.1 on page 280, there is a statement about PAM4_Mapping stating that 
it is ignored if Modulation is not defined.  Randy noted this needs to be 
changed if we want it to be used with Modulation_Levels and not ignored.  New 
text was added to draft 20 to allow a default for PAM4_Mapping with 
Modulation_Levels not declared, and to declare PAM4_Mapping is ignored when 
Modulation_Levels is set to any value other than 4. 


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

AR: Arpad to send an updated draft 20 of BIRD213.1 to the ATM list.
    
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Next meeting: 12 April 2022 12:00pm PT (no meeting during DesignCon week)
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IBIS Interconnect SPICE Wish List:

1) Simulator directives