IBIS Macromodel Task Group

Meeting date: 04 October 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:                       Hanfeng Wang
                              GaWon Kim
Intel:                      * Michael Mirmak
                            * Kinger Cai
                            * Chi-te Chen
                              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
                              Yifan Ding
Rivos                         Yansheng Wang
SAE ITC                       Michael McNair
Siemens EDA (Mentor):       * Arpad Muranyi
Teraspeed Labs:             * Bob Ross
Waymo:                        Zhiping Yang
Zuken USA:                    Lance Wang

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

--------------------------------------------------------------------------------
Opens:

- None.

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Review of ARs:

- Chulsoon to update the Pre-driver PSIJ Sensitivity BIRD and send draft3 to
    the ATM list.
  Done
	
- Kinger to update the SPIM BIRD and send draft3 to the ATM list.
  Done

- Kinger to update the PSIJ Sensitivity BIRD and send draft2 to the ATM list.
  Not done

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Call for patent disclosure:

- None.

-------------------------
Review of Meeting Minutes:

Arpad asked for any comments or corrections to the minutes of the September 27th
meeting.  Randy moved to approve the minutes.  Michael seconded the motion.
There were no objections.

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New Discussion:

Clock_times clarification BIRD draft:
Arpad shared the BIRD draft 0.2.d. Arpad noted most of the changes are in the 
summary section.  

The document shows the original IBIS 7.1 text for the clock_times definition.  
Then it shows the IBIS 7.2 draft text that incorporates changes from BIRD213.1 
and BIRD217 highlighted in yellow.  Then proposed changes are in 
strike-throughs (removing existing text) and cyan highlights.

Bob asked for the draft to be renamed to "draft 3".  Bob questioned why the 
BIRD is written against a spec that is not approved.  Michael noted the BIRD 
is attempting to show all changes to this section of IBIS 7.1 including the 
changes from BIRD213.1 and BIRD217 for the purpose of editorial work.  Walter 
asked if this work from Editorial was intended for IBIS 7.2.  Arpad confirmed 
that a BIRD from the Editorial group is being issued to capture these 
significant editorial changes.

Arpad noticed the current clock_times definition considers clock_times as an 
output only.  When clocked AMI GetWave models have a clock_times input as a 
waveform or clock times, this usage of clock_times is not explained.  

Walter noted that as an input, clock_times describes when edges of clock reach 
the pad.  As an output these are different clock times.  There is nothing 
wrong with a memory area containing different data as input or output.  Arpad 
wanted to clarify what this data means.  Walter read the text, and it doesn't 
change the meaning of clock_times.

Some added text notes sampling times applying to the "DQ" models, referenced 
as single or dual input Rx AMI_GetWave functions.

Arpad noted text for waveforms to be "symmetric around the horizontal axis" 
was added to clarify expectations. Ambrish asked if DQS should always be 
differential and therefore swinging around zero volts.  Arpad noted we'd need 
a voltage sampling level if it was not.  Walter did not like the description 
of "symmetric".  Arpad will note the need to fix this description [AR].  

Randy added that the "sampling time calculations" was a way to generalize the 
sampling concept of DQS on DQ without describing details of a technology like 
DDR5 that may add offset between DQS and DQ internal to the DQ DLL.

Ambrish questioned the need for a statement about the waveform voltage samples 
being monotonic in time.  Walter thinks the EDA tool could not make a waveform 
that is non-monotonic in time.  Arpad thought we should add an analogous 
statement about waveforms since clock_times described a monotonic requirement 
for clock times.  Walter described the use of EDA tools to create passthrough 
functions, and Arpad noted this statement exists in the Rx_Use_Clock_Input 
section. Ambrish and Walter did not think the statement "discontinuities in 
the waveform sample" was a correct statement.  Ambrish noted sample interval 
is already defined.

Ambrish thought clarification text would be better added to the end of 
sections of existing text if possible. Arpad noted that the clock_times 
section could be reorganized by the three cases and describe the rules for 
each case.

- Bob: Motion to adjourn.
- Ambrish: Second.
- Arpad: Thank you all for joining.

AR: Arpad to fix description of "symmetric" in the clock_times clarification 
BIRD.
AR: Kinger to update the PSIJ Sensitivity BIRD and send draft2 to the ATM list.
    
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Next meeting: 11 October 2022 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives