IBIS Macromodel Task Group

Meeting date: 21 May 2013

Members (asterisk for those attending):
Agilent:                    * Fangyi Rao
                            * Radek Biernacki
Altera:                       David Banas
                              Julia Liu
                              Hazlina Ramly
Andrew Joy Consulting:        Andy Joy
ANSYS:                        Samuel Mertens
                            * Dan Dvorscak
                            * Curtis Clark
                              Steve Pytel
                              Luis Armenta
Arrow Electronics:            Ian Dodd
Cadence Design Systems:       Terry Jernberg
                            * Ambrish Varma
                              Feras Al-Hawari
                              Brad Brim
                              Kumar Keshavan
                            * Ken Willis
Cavium Networks:              Johann Nittmann
Celsionix:                    Kellee Crisafulli
Cisco Systems:                Ashwin Vasudevan
                              Syed Huq
Ericsson:                     Anders Ekholm
IBM:                          Greg Edlund
Intel:                      * Michael Mirmak
Maxim Integrated Products:    Mahbubul Bari
                            * Hassan Rafat
                              Ron Olisar
Mentor Graphics:            * John Angulo
                              Zhen Mu
                            * Arpad Muranyi
                              Vladimir Dmitriev-Zdorov
Micron Technology:            Randy Wolff
                              Justin Butterfield
NetLogic Microsystems:        Ryan Couts
Nokia-Siemens Networks:       Eckhard Lenski
QLogic Corp.                  James Zhou
SiSoft:                     * Walter Katz
                            * Todd Westerhoff
                              Doug Burns
                            * Mike LaBonte
Snowbush IP:                  Marcus Van Ierssel
ST Micro:                     Syed Sadeghi
Teraspeed Consulting Group:   Scott McMorrow
                            * Bob Ross
TI:                           Casey Morrison
                              Alfred Chong
Vitesse Semiconductor:        Eric Sweetman
Xilinx:                       Mustansir Fanaswalla
                              Ray Anderson

The meeting was led by Arpad Muranyi

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Opens:

- Arpad: The last day to submit BIRDs for 6.0 is this Friday

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Call for patent disclosure:

- None

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Review of ARs:

- Fangyi update BIRD 156 per task group feedback
  - Done, BIRD 156.2

- Walter to write new BIRD for [Repeater/Retimer Pin] keywords.
  - Done, combined into BIRD 156.3
  - This has been emailed.
  - SiSoft should be added to the author list.


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New Discussion:

Interconnect Task group report
- Michael M: At the meeting last Wednesday we discussed:
  - BIRD 161.1
  - A new format and structure for EMD
  - A ports presentation from Walter

Redriver BIRD 156.3:
- Fangyi and Walter expressed a desire to work out final details soon.
- Todd: We have a lot of models out there, it would be good to finalize this

- Fangyi showed the BIRD and described the changes
- It was clarified that "repeater" is the generic term for either redriver or retimer
- Arpad: Some important information in the analysis section needs to be in the
  main section so it will be in the spec
- Fangyi: A retimer requires RX AMI_GetWave() outputting clock_times
  - What if the RX has no GetWave?
- Walter: Statistical analysis is still possible without GetWave using jitter parameters
  - We could require GetWave
- Arpad: Can a retimer not have clock ticks?
- Walter: The simulator can derive clocking
- Todd: Without a CDR there can be no accurate time domain
- Fangyi: We should require GetWave
- Ambrish: Init_Returns_Impulse would not be required?
- Fangyi: That makes it easier for the model developer too

- Fangyi: The redriver RX output drives the TX input continuously
- Ambrish: But the TX has Pullup and PullDown, how is the stimulus generated?
- Arpad: Only [External Circuit] can have a pure analog input like that
- Todd: We derive an impulse response for each channel in advance
  - A digital input is used for that part
  - The result of that is used for the algorithmic simulation
- Arpad: It is confusing that it says the "TX analog model" is driven
- Todd: It should say "algorithmic"
- Fangyi: We are talking about how the TX algorithmic drives the TX analog
  - The order is given in the paragraph
- Arpad: In simulation the order is not the same
- Fangyi: It is the same
- Michael M: We are back to the disagreement on whether TX input is analog or digital
- Fangyi: Do we agree on the flow order?
- Todd: In the reference flows the impulse response is passed to TX Init
  - So for Init TX analog comes before algorithmic
  - For GetWave it is reversed
- Walter: There are 3 ways to derive impulse response for the downstream channel
  - BIRD 158 describes Tstonefiles
  - The analog channel includes the TX driver
- Arpad: How can the sentence be changed to make it clear?
- Todd: At first I would have changed "analog" to "algorithmic"
  - Do we agree the upstream and downstream channels are evaluated independently?
- Fangyi: Yes
- Todd: The repeater TX Init will receive repeater RX algorithmic Init output
- Fangyi: No, it will get the analog
- Todd: You are right
  - The repeater RX GetWave gets the TX GetWave output
  - Once the impulse response is derived, the analog models can be thrown away
- Ambrish: So the sentence is not needed?
- Fangyi: Yes, it could be deleted
- Arpad: This should be handled by email, but it has to be done by Friday
- Fangyi: The issue is between Arpad and Ambrish, and should be discussed here
- Todd: The picture is useful, but the sentence only complicates things
- Fangyi: The details are still given in the next paragraph
- Fangyi removed the "Note that" sentence

- Fangyi: Step 8 is split into a and b for redriver and retimer
- Walter: Agree that we should add the statement about half UI offset
- Ambrish: The new signal is produced by the simulator, not the model?
- Michael M: In a real device there would be a bit pattern
- Walter: After resampling it should have the same bits
- Todd: Fangyi is right, passing a waveform forward is not helpful
  - Letting the redriver RX recover the signal lets us do upstream diagnostics
  - The retimer RX and TX do not know they are part of a retimer
- Ambrish: What do the physical devices do?
- Walter: They do actually recover the waveform
- Todd: The RX signal may be 80mV and it is converted to +/- 0.5V
- Arpad: I thought the TX input was not digital
- Todd: For a redriver
- Ambrish: Where does it say the digital signal is not created?
  - It would be nice to avoid it if not necessary
- Todd: The current proposal just allows for better analysis

- Fangyi: I sent an email asking about a noise issue
- Walter: RX noise affects the BER, not the waveform

- Fangyi: Walter made changes for step 7a and 7b
- Walter: Both RXs have a BER, and the repeater itself can have jitter
- Ambrish: We decided to use numbered channels, not "upstream" and "downstream"
- Fangyi made this change

- Arpad: It should stated that the Repeater AMI param is in Reserved_Parameters
- Bob: It also needs usage rules
- Walter: It should "require" GetWave_Exists, not have an "if"
- Fangyi: Is this in the TX or RX AMI file?
- Walter: It could be in both
- Michael M: If in one only does that mean a non-repeater model could be used?
- Ambrish: The RX model for this is generic, any RX would do
- Todd: It's not a big deal to add this keyword to it and use it
- Arpad: It will not be clear why this has to be added
- Todd: It really should be handled at component level, but still better to handle in AMI
- Ambrish: Do we need it in both places?
- Todd: No
- Bob: This is global, it will apply to all RX pins
- Todd: Most users don't look at AMI files closely
  - It is better to make sure the tool gets it right
- Arpad: If not in the AMI file can the tool figure it out?
- Todd: It would not know if it is a redriver or retimer
  - It might figure it out from clock ticks, but sometimes those are delayed
- Michael M: Can we mix and match TX and RX?
- Todd: There is a way to take a full model and turn things off to use it

- Fangyi: I will update and send to Walter
  - Then it will go to the reflector
- Arpad: It has to be submitted to Open Forum by Friday
- Todd: We should have an edited version for all to review by tomorrow
- Michael M: It needs to be receive by Open Forum before Saturday
  - Minor editorial changes can be approved at voting time

- Fangyi changed "Repeater" to "Repeater_Type", with approval

- Walter: I will work with Bob on the Labels BIRD

- Radek: I have comments on BIRD 158
- Ambrish: I don't think we need it
- Walter: It serves a need that has been discussed

AR: Fangyi submit updated BIRD 156 to Open Forum
AR: Mike post update BIRD 156 to ATM web

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Next meeting: 28 May 2013 12:00pm PT

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IBIS Interconnect SPICE Wish List:

1) Simulator directives
