Minutes from the 16 Jul 2019 IBIS ATM meeting are attached.
Randy
IBIS Macromodel Task Group
Meeting date: 16 July 2019
Members (asterisk for those attending):
ANSYS: Dan Dvorscak
Curtis Clark
Cadence Design Systems: Ambrish Varma
Ken Willis
Intel: Michael Mirmak
Keysight Technologies: * Fangyi Rao
Radek Biernacki
Ming Yan
Stephen Slater
Maziar Farahmand
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. Randy Wolff took the minutes.
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Opens:
- None
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Review of ARs:
- Fangyi to write new BIRD draft for DC_Offset.
- Done
- Arpad to submit [C Comp Model] BIRD to Open Forum.
- 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 July 9
meeting. Randy moved to approve the minutes. Bob seconded the motion. There
were no objections.
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New Discussion:
New DC_Offset BIRD draft from Fangyi:
Fangyi shared a PowerPoint "BIRD_enable_single_ended_signal_in_AMI.pptx".
Motivation is the same as the BIRD197 DC_Offset BIRD. DC_Offset usage is
changed to In or InOut. Defaults are 0 V. In the case of Usage In, the output
value is assumed to be 0 V.
Arpad asked about proposal item #1. Is the default value of DC_Offset 0
appropriate or should it default to the same as the input value? This affects
item #5. Fangyi doesn't want to add the input value to the output waveform.
He doesn't want to mix input and output.
Fangyi showed two examples showing how the DC_Offset and NRZ_Threshold work
together, along with multiple ways to use the parameters to get the same result.
Randy asked if these parameters would ever be used with differential SerDes
buffers. Arpad noted he was reminded of his question to the reflector a
couple weeks ago about the use of the term threshold. Fangyi said first
assume Rx_receiver sensitivity is 0. If you have a threshold, above the
threshold is 1 and below the threshold is 0. Arpad commented that we are
looking only at a difference waveform. Fangyi noted you should look at it
with comparators. Randy noted in SerDes we assume the threshold is 0. Fangyi
confirmed this, and Receiver_Sensitivity adds uncertainty to the switching
level, ideally 0.
Arpad noted he sent comments by email to Fangyi. Fangyi responded that he
updated some descriptions in his presentation, but he needs to make the change
in the BIRD draft.
Arpad stated it needs to be defined more clearly what happens when Get_Wave
returns a value in DC_Offset. Fangyi responded the only value that matters
is the value returned by Init. Arpad asked if GetWave would ever return the
value. Fangyi noted that GetWave could return the value, but only the value
from Init is used to recover the waveform.
Wei-hsing asked about the GetWave flow. Radek noted GetWave cannot handle
InOut parameters. This was discussed during the backchannel discussion.
Arpad asked if we should require the value to be returned only in Init and
prohibit it elsewhere. Fangyi thinks it doesn't matter if GetWave returns
the DC_Offset value, since it is not used.
Fangyi asked about Arpad's comment on saying "Rx equalizer output". Fangyi
noted an Rx may not have an equalizer. Fangyi suggested "Rx algorithmic model
output".
Fangyi agreed with adding "may" to "EDA tools may obtain the complete waveform
at the Rx output by" after Arpad described the EDA tool could process the
waveform in different ways, so it is best not to dictate what the EDA tool
should do.
Walter commented that he is ok with DC_Offset being In or InOut, and the rest
of the BIRD is fine.
Bob asked if it would be helpful to put the examples in Fangyi's last two
slides into the BIRD template. Arpad suggested adding this in the background
information section.
Bob asked if the intent was to supersede BIRD197.3. Arpad wondered if it
should be a revision to BIRD197.3 or a new BIRD. Walter thought it would be
easier to become a new draft of BIRD197.3, and he was ok with this becoming
BIRD197.4.
AR: Fangyi to create BIRD197.4 incorporating changes from his new BIRD and
comments.
There was a motion to adjourn and a second to the motion. The meeting
adjourned.
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Next meeting: 23 July 2019 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
