IBIS Macromodel Task Group

Meeting date: 08 March 2016

Members (asterisk for those attending):
ANSYS:                      * Dan Dvorscak
                            * Curtis Clark
Broadcom (Avago):             Xingdong Dai
                              Bob Miller
Cadence Design Systems:     * Ambrish Varma
                              Brad Brim
                              Kumar Keshavan
                              Ken Willis
Cisco:                        Seungyong (Brian) Baek
eASIC:                      * David Banas
                              Marc Kowalski
Ericsson:                     Anders Ekholm
GlobalFoundries:              Steve Parker
Intel:                      * Michael Mirmak
Keysight Technologies:      * Fangyi Rao
                            * Radek Biernacki
                            * Ming Yan
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


The meeting was led by Arpad Muranyi.

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Opens:

- Ming Yan of Keysight Technologies introduced himself to the ATM group.  He
  works closely with Fangyi and Radek, and he has been working on IBIS and AMI
  modeling for 10 years.  He has previously attended Open Forum meetings and
  summits, and he was co-author of a paper on IBIS overclocking issues.

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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]
- Michael M.: Motion to approve the minutes.
- David: Second.
- Arpad: Anyone opposed? [none]

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New Discussion:

New Redriver Flow BIRD:
- Fangyi: [Sharing an updated version of his presentation
           "AMI Simulation Flow Round 3"]
  - Thinking about ways for the tool and model to work together.
  - Introduce two new Reserved_Parameters:
    - Simulator_Supports_Augmented_Rx_Init_Impulse_Matrix
      - Optional, Boolean, Type Input, Default value False
      - Used by the EDA tool to tell the model if it supports the new flow.
    - Rx_Init_Supports_Augmented_Impulse_Response
      - Optional, Boolean, Type Info, Default value False
      - Tells the EDA tool if the model supports the new flow.
  - Three scenarios in which the new flow is supported by the model, the tool
    or both.
    - 1. Model does not support new flow.
      - Tool follows existing flow.
    - 2. Model and tool support the new flow.
      - Tool tells Rx model it is running the new flow.
      - Tool provides augmented IR matrix.
      - Tool follows new flow.
    - 3. Model supports new flow, tool does not.
      - Tool does not indicate that it follows the new flow.
      - Tool passes legacy IR matrix to the Rx model.
      - If model supports legacy flow, then it follows it.
      - If model does not support legacy flow, its AMI_Init() function returns
        an error.
- Discussion: Walter noted that he would prefer not to have "Supports" in the
  names of the new parameters.  He also stated that a single parameter could be
  used for the model to indicate support to the tool and vice versa.
  Radek agreed that a single parameter should be sufficient.  Fangyi reviewed
  the slides detailing the augmented flow proposal (the slides originally
  presented in the Feb 16th meeting).  Walter noted that if we were going to
  consider augmenting the IR matrices and fully revamping the flow, he would
  have some suggestions for augmenting the IR matrix for the Tx AMI_Init() as
  well.  With respect to the "Normal Time Domain Flow: Get Wave Tx" (slide 4),
  Walter had several questions/proposals:
    - One of the three things the Rx AMI_Init() returns is the non-DFE portion
      of the Rx convolved with the analog channel IR.  Instead, why not simply
      return the non-DFE portion of the Rx itself?  The tool can do that
      convolution instead.
    - The three things returned by the Rx AMI_Init() would then be the DFE
      portion of Rx, the non-DFE portion of Rx, and the total containing the
      entire Rx applied to the entire input IR.
    - The third returned item is just what we have with the existing flow.
    - We would no longer need to pass the hRx,in partial (analog channel IR
      itself).
    - This simplified flow would make it easier for a model to support the
      legacy and new flows.
  On first reflection Fangyi agreed with Walter's comments and said the flow
  could be reduced in this manner.  Mike LaBonte then asked if not having the
  analog channel IR combined with the non-DFE would deprive the model of any
  special processing needed to align the cursor.  Fangyi said that was a good
  question, and that different models would have different ways to locate the
  main cursor dependent on their CDRs.  For this reason, it might be necessary
  to pass the analog channel IR to the model.  After the review, Walter noted
  that Fangyi's proposal would solve the original problem of an Init() only
  terminal Rx() not being passed the complete IR, including upstream effects,
  it needs for its optimization.  However, he said this proposal still fell
  short if the redriver's Tx wanted to optimize itself.  Fangyi agreed that this
  was true, because the redriver Tx was not presented with the effects of the
  upstream channel.  Walter noted that this was a separate issue.  He said it
  was the reason his proposal contained a new parameter indicating whether the
  Tx optimizes itself.

- Arpad: Thank you all for joining.
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Next meeting: 15 March 2016 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
