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IBIS INTERCONNECT TASK GROUP
http://www.ibis.org/interconnect_wip/
Mailing list:
ibis-interconnect@xxxxxxxxxxxxx<mailto:ibis-interconnect@xxxxxxxxxxxxx>
Archives at //www.freelists.org/archive/ibis-interconn/
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Attendees from December 2 Meeting (* means attended at least using audio)
ANSYS Curtis
Clark
Cadence Design Systems Bradley Brim
Cisco David
Siadat
Intel Corp. Michael
Mirmak*
Keysight Technologies Radek Biernacki
Mentor Graphics Arpad Muranyi*
Micron Technology Justin Butterfield*,
Randy Wolff*
SAE ITC Maureen
Lemankiewicz, Logen Johnson
Signal Integrity Software Walter Katz*, Mike
LaBonte*
Teraspeed Labs Bob Ross*
University of Aveiro in Portugal Wael Dghais
Michael Mirmak called the meeting to order. He thanked Arpad Muranyi for
running the previous meeting and Justin Butterfield for taking the minutes.
Arpad moved to approved the minutes. Mike LaBonte seconded. There were no
objections and the motion carried.
No patents were declared.
During Opens, Bob Ross raised the issue of the "probe" term and its syntax.
This topic will be taken up at a future meeting.
Michael asked about key points raised for Draft 26 as discussed in the last
meeting.
Bob noted that the team must eventually settle on terminology. For instance,
the table on (non-markup) P. 10 features qualifiers "pin_name", "signal_name",
"bus_label", and "pad_name", which should all be lower case.
Arpad asked whether subparameters are capitalized. Bob responded that both
pin_name and signal_name must be lower-case. Arpad noted that these tokens are
subparameters but are on the same line as [Pin]. Michael added that these are
effectively in-line subparameters of [Pin]. This is similar to the Terminal
line issue in the Draft Interconnect document.
Mike LaBonte observed that reserved words need clarification in the main IBIS
document. Bob stated that column headers have a special treatment relative to
subparameters, though this may not be explicit.
Michael noted that how to offset "Aggressor" is a problem, in that "Aggressor"
itself is a token, while everything else on that line is a field for a string
entry.
Arpad asked whether we done with the technical work on the Interconnect draft.
Michael responded that, except for settling "probe", examples/drawings and
spelling checks are the only things left to do.
Bob: delete [Die Supply Pads] entirely. Walter Katz and Randy Wolff discussed
whether we would ever want to have a package model that was separate from the
die pads, with more than one ground pad. Randy noted that support is needed
for some number of terminals on the die-package interface. The solution must
support both more simple PDN models or more complex PDN models.
Bob asked about the difference between [Die Supply Pads] and [Bus Labels].
Walter suggested that [Bus Labels] are not needed and should be deleted. Bob
responded that we are intermixing pins and labels. Walter replied that they
are independent concepts; the labels are ways of grouping them.
Michael asked whether these are the same concept. Bob replied that one or the
other is useless, and one becomes the other. Walter stated that the terms are
ways of shorting nodes together; all the terminals on that Bus Label are
shorted together. You treat them as a group to be shorted together. Walter
noted that the approach is similar to MCP (Model Connection Protocol).
Mike noted that Bus Labels was a difficult concept for Summit attendees. The
phrase appears in the main IBIS document, but only under [Pin Mapping] and only
three times. Walter agreed that it has been problematic; Signal_name is a
better concept.
Mike took an action to come up with new diagrams, corresponding to the document
examples, based on Interconnect BIRD presentation. He added that, in the
current document, some two-port networks didn't have space for a reference;
these should be removed.
Michael noted that, in addition to the drawings, for the next meeting, the team
will discuss whether to maintain "probe" in the document, and will finalize Bus
Labels vs. Die Supply Pads, based on diagrams discussed.
Walter noted that previous discussions have focused on using correct global
ground. However, 99% of people are not using power-aware networks with local
grounds. This is not a bad thing, but you have the ability to add those nodes
if you are concerned about the currents.
Arpad asked whether it was a bad precedent to have capacitors with links to
global grounds. Walter raised a concern about references to W-elements. Arpad
replied that this just a theoretical reference; to have a signal reference for
other signals in the W-element, use an additional signal in the W-element
structure.
Walter stated that there is an apparent distinction between using node zero at
all and using it as a reference.
On probe, Bob commented that, if we are to add it to the table as an allowed
Terminal type, what are the pin_name, signal_name, etc. entries to be? It's a
nice feature, but it needs to be checked (one cannot have I/O_Buffer as a
pin_name, for example). Is the EDA tool responsible for it? Walter replied
that EDA tools should not have special visibility and he does not think it
should be included.
Walter asked whether a vote to remove probes would be needed.
Bob moved to adjourn the meeting. Mike seconded. The meeting adjourned.
