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
