Minutes from the 03 November ibis-atm meeting are attached.
IBIS Macromodel Task Group
Meeting date: 03 November 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
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:
- None.
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Call for patent disclosure:
- None.
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Review of ARs:
- None.
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Review of Meeting Minutes:
- Arpad: Does anyone have any comments or corrections? [none]
- Bob R: Motion to approve the minutes.
- Arpad: Second.
- Arpad: Anyone opposed? [none]
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New Discussion:
Item #6: New Redriver Flow BIRD.
- Discussion: Walter said that he had talked to Vladimir and Fangyi at the
EPEPS IBIS Summit. Walter said he understood Fangyi's points, and summarized
the issue. When every device has an Init() that returns an impulse, then our
statistical flow is okay, though we still need the correction to make sure the
final Rx Init() sees the IR characterizing the entire upstream system. If
every device has a GetWave(), then our time domain flow is fine. The problem
with the redriver flow occurs when each device has an Init() that returns an
impulse, and each device except the final Rx has a GetWave(). In that case,
the redriver Init() flow is defined, but its input to the final Rx should be
the combined IR of the entire system. If you then try the GetWave() flow, the
output of the redriver's Tx contains all the upstream effects. But the
output of the final Rx's Init() would also contains all the upstream effects,
and convolving the two would double count all the upstream effects. Walter
stated that he agreed with Fangyi's proposal that an extra IR had to be
presented to each downstream Rx. This additional IR would be the IR of the
channel that immediately preceded the Rx. This would allow the Rx Init() to
return an IR that had the correct equalization applied only to the last
channel's IR.
Discussions then turned to how this additional information could be passed
to the Rx Init(). Arpad suggested that we could do it without modifying the
function signature of the AMI_Init() call. There was general agreement that
the additional IR could be passed as part of the IR matrix, and an additional
Reserved Parameter or some other mechanism could be used to make it clear to
the Init() call where the various IRs were located in the matrix. Fangyi then
suggested that if we did extend the current IR matrix concept then the same
Init() processing could be used for statistical or time domain flows. If the
Init() call were to apply the equalization to both the overall IR and the
most-recent-channel IR, then the EDA tool could just use the resulting overall
IR for the statistical flow, or use the resulting most-recent-channel IR for
the time domain flow.
Walter suggested that Fangyi might take the redriver flow BIRD Walter had
started and update it with his proposals. Fangyi agreed.
Item #7: Language corrections regarding "ground".
- Discussion: Radek mentioned that in the previous meeting we had discussed
the process and logistics for making these changes. Arpad suggested that we
start with a top level review of the nine topics presented in Radek's summary
email [repeated below verbatim]:
1. Is the global node “0” assumed in any discussion or any diagram?
2. Under what circumstances the global node “0” can be used by the user or the
EDA tool?
3. What can be done if any IBIS-ISS subcircuit contains a global node “0”?
4. What nodes is the C_comp capacitance connected to?
5. What is the impact of different [Pulldown Reference] and
[GND Clamp Reference] values?
6. What is the relationship between non-zero [Pulldown Reference],
[GND Clamp Reference] and the signal I/O reference node in the absence of
the [Pin Mapping] keyword?
7. What is the relationship between non-zero [Pulldown Reference],
[GND Clamp Reference] and the signal I/O reference node when the
[Pin Mapping] keyword is present?
8. What is the relationship between pulldown_ref, and/or the gnd_clamp_ref bus
declaration under the [Pin Mapping] keyword and the signal I/O reference
node?
9. Do we need to extend the [Pin Mapping] definition to cover signal I/O
reference bus declaration?
Radek reviewed each of his proposed topics. There were some high level
questions and comments, but it was agreed that we would take on each topic in
full detail at subsequent meetings.
- Arpad: Now is a good stopping point.
- Thank you all for joining.
AR: Fangyi to update Walter's Redriver Flow BIRD proposal.
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Next meeting: 10 November 2015 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
