Minutes from the 7 Apr 2015 ibis-atm meeting are attached. Also
documents shown during the meeting are posted to the work archive.
*DATE* AUTHOR
<http://www.eda.org/ibis/macromodel_wip/archive-author.html>
ORGANIZATION <http://www.eda.org/ibis/macromodel_wip/archive-org.html>
TITLE <http://www.eda.org/ibis/macromodel_wip/archive-title.html> FORMATS
07-APR-2015 Walter Katz SiSoft PAM4 BIRD draft 15 (zip
<http://www.eda.org/ibis/macromodel_wip/archive/20150407/walterkatz/PAM4_BIRD_draft_15.zip>)(pdf
<http://www.eda.org/ibis/macromodel_wip/archive/20150407/walterkatz/PAM4%20BIRD%20draft%2015/PAM4_BIRD_rev15.pdf>)
07-APR-2015 Randy Wolff Micron Technology C_comp Model Using
IBIS-ISS
BIRD draft 6 (zip
<http://www.eda.org/ibis/macromodel_wip/archive/20150407/randywolff/C_comp_Model_Using_IBIS-ISS_BIRD_draft_6.zip>)(dir
<http://www.eda.org/ibis/macromodel_wip/archive/20150407/randywolff/C_comp%20Model%20Using%20IBIS-ISS%20BIRD%20draft%206/>)
Mike
IBIS Macromodel Task Group
Meeting date: 07 April 2015
Members (asterisk for those attending):
Altera: * David Banas
ANSYS: * Dan Dvorscak
* Curtis Clark
Avago (LSI) Xingdong Dai
Cadence Design Systems: * Ambrish Varma
Brad Brim
Kumar Keshavan
Ken Willis
eASIC David Banas
Ericsson: Anders Ekholm
IBM Steve Parker
Intel: Michael Mirmak
Keysight Technologies: * Fangyi Rao
* Radek Biernacki
* Nicholas Tzou
Maxim Integrated Products: Hassan Rafat
Mentor Graphics: * John Angulo
* Arpad Muranyi
Micron Technology: * Randy Wolff
Justin Butterfield
QLogic Corp. James Zhou
Andy Joy
eASIC Marc Kowalski
SiSoft: * Walter Katz
Todd Westerhoff
* Mike LaBonte
Synopsys Rita Horner
Teraspeed Consulting Group: Scott McMorrow
Teraspeed Labs: * Bob Ross
(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:
- Michael M update AMI Directionality BIRD
- No update
- Walter and Randy produce C_comp BIRD.
- Arpad: Some work has been done and this has been posted.
- Arpad to review IBIS specification for min max issues.
- In progress.
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New Discussion:
Pin merging:
- Arpad: I had proposed some changes.
- Arpad showed an example for a proposed change.
- Arpad: Bob had proposed a new keyword instead of a subparameter.
- This shows [Merged Pins], prepared by Randy.
- Randy: Line wrapping needs to be allowed.
- Arpad: In the second format the main pin follows the keyword.
- Other connected pins are on the next line.
- Radek: How does this relate to IBIS line continuation rules?
- Bob: I prefer the two line format.
- You can comment them that way.
- Walter: These are not consistent with the pin list above.
- For example K9 is absent.
- Arpad: That is because there is no model for K9.
- Radek: But it must be on the component.
- Walter: These issues will go away with the new package model.
- Bob: This doesn't force using signal names for merged pins.
- Arpad: We found that [Pin Mapping] did not work the same way in each tool.
- But this BIRD addresses just the ambiguity for pins that are not in [Pin
Numbers].
- The new package model capability will fully address it.
- John: This can create a set of shorted pins that is not the same set as [Pin
Mapping].
- Arpad: It's the same capability.
- Bob: This can be used only with [Pin Mapping] present.
- John: You can have two buffers on the die side using the same group of
shorted pins.
- Arpad: That is ruled out.
- Bob: We want to avoid shorting power and ground.
- Arpad: Near the die features become smaller.
- It makes more sense to combine those.
PAM4 BIRD:
- Walter: The BIRD draft is up to revision 14 now.
- I will send it with any changes to Mike for posting.
- We should be able to forward it to the Open Forum with a recommendation.
- It will not be ready for this Friday however.
- Arpad: We should review the changes.
- Walter showed the draft PAM4 BIRD.
- Walter: The Modulation parameter can be Info if there is only one value.
- It has to be In to have multiple values.
- Bob: The Default must be <string_literal>.
- Radek: Why does the Default have to be here at all?
- Bob: That's how our rules work.
- Walter: For List format Default makes sense, but not for Value.
- Walter: PAM4_Mapping maps levels to symbols.
- Grey code "0132" is the default.
- Bob: Again the Default is a <string_literal>.
- Even though it is Value only.
- Walter: We have three thresholds for PAM4.
- Arpad: We do not assume center for the middle threshold?
- Walter: That is up to the model maker.
- We allow InOut in case the model chooses it.
- If not specified the EDA tool must determine thresholds.
- Arpad: Is it specified how to do that?
- Walter: It is up to the tool.
- The thresholds really should be given.
- There is also a PAM4_Receiver_Sensitivity, only for the middle threshold.
- Bob: The Default should be <numeric_literal>.
- We should support Dep usage.
- Radek: Dep should be allowed for anything that can be Out.
- Walter: We have timing offsets for the upper and lower eyes.
- Bob: The Default must be described in the text.
- Arpad: Scott McMorrow was asking about non-linearity.
- Fangyi had said AMI_GetWave could handle it.
- That should be explained.
- Walter: It depends on what causes the non-linearity.
- It will not happen in the RX analog section.
- Voltage levels there are small, it will be linear.
- In the TX there could be a voltage lookup table based on previous symbols.
- It does not have to be a classic FFE.
- Any non-linearity there probably is not about saturation.
- Arpad: Fangyi said it might be a saturation effect.
- Walter: Maybe only the impedance changes, but that's not voltage.
- Arpad: This assumes the impulse response is done with an NRZ level.
- Walter: It can be thought of as pulse or step too.
- Fangyi: Should we allow Out for PAM4_Mapping?
- Walter added a note for that.
- We need to ask IC vendors about this.
- Fangyi: We need to discuss the bit_time argument in AMI_Init
- Walter: In PAM4 we have a symbol, not a bit.
- For PAM4 it will be symbol time.
- Mike: We could rename it to symbol_time
- Arpad: We could say bit_time is scaled by symbols/bit.
- Ambrish: Other places in the IBIS specification might need to change for this.
AR: Walter send updated PAM4 BIRD to Mike for posting.
C_comp:
- Randy showed C_Comp Model BIRD draft revision 6.
- Randy: ISS has been changed to IBIS-ISS.
- An example has been reformatted to insert a format column.
- A figure has been updated.
- Radek: There is no A_gnd in there, we will need that.
- David: Is the numbering of names required?
- Randy: That is done to avoid conflicts.
- The unnumbered nodes are at predefined locations.
- Bob: Corner has to be described as a model corner.
AR: Randy send updated C_comp BIRD to Mike for posting.
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Next meeting: 14 Apr 2015 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
