Minutes, IBIS Quality Task Group

20 August 2019

11:00-12:00 EST (08:00-09:00 PST)

ROLL CALL

Intel Corp.                         Michael Mirmak
Mentor, a Siemens Business          Arpad Muranyi
Signal Integrity Software:        * Mike LaBonte
SPISim                              Wei-hsing Huang
Teraspeed Labs:                   * Bob Ross
Zuken USA:                        * Lance Wang

Everyone in attendance marked by *

NOTE: "AR" = Action Required.

-----------------------MINUTES ---------------------------
Mike LaBonte conducted the meeting.

Call for IBIS related patent disclosures:

- None

Call for opens:

- None

Review of previous meeting minutes:
Minutes from the August 13 meeting were reviewed.  Lance Wang moved to approve the minutes.
Bob Ross seconded.  Without objection the minutes were approved.


ARs:
- Mike LaBonte to write descriptions of IBIS-ISS parser levels for quotes
  - Done


New IBISCHK bugs:
Bob Ross said there was an IBISCHK bug related to [Series Switch]. It failed to detect
missing arguments.  Our website had a [Series Switch] example. Bob will check IBIS 7.0
to make sure arguments are always required.  It can be fixed in IBISCHK7.0.1.

AR: Bob Ross to write bug report for [Series Switch] argument bug


IBISCHK700 parser development:
Bob Ross said overlap rules were being worked on. Some qualifiers specify subsets
of others, for example pin names and signal names.  Atul was implementing the rules
specified by Bob.

Our Aggressor_Only rules seemed complete. This will be confirmed in the ATM meeting
later, and sent to Atul if we agree.  As currently implemented, a valid testcase would
fail. Bob hoped to get the feedback to Atul tomorrow evening.  The issues point to
the need for new clarification BIRDs.


IBISCHK7 source code license:
There was no change from the previous week, with three agreements signed and one
paid. It is still under legal review at some companies.


IBIS-ISS parser:
Mike LaBonte showed RFQ_ISSCHK_v1.docx. He described the contents.  Mike added model
names to the list of names requiring character set enforcement.  He said .include file
recursion was originally specified for level 2, but he had placed it in level 1 due
to ATM discussion about that.  Mike moved .include recursion loop detection to level 1
checking because it was an essential part of recursion.

Low impedance path tracing was a level 4 option item. Mike said the purpose of that
was to verify that two terminals that are effectively declared as providing a signal
path by pin_name association actually could conduct a signal.  Bob Ross noted that
the signal might be AC coupled. Mike removed that line item.

API for controlled integration with applications was an optional level 4 item. Mike
explained that a minimal level 4 implementation would use something like linked lists
for data representation in memory, and the checking code could use those directly. But
if the ISSCHK code would be used as the front end parser for another program, a stable
function or object API would be expected.

Mike said one check that could not be performed by either IBISCHK or ISSCHK was the
verification that an IBIS-ISS [Interconnect Model] had the same number of terminals as
the called subckt.  Bob Ross said one way to resolve that would be to include minimal
IBIS-ISS parsing in IBISCHK, just for that purpose.  Mike suggested not having two
IBIS-ISS parsers, preferring to embed all of ISSCHK in IBISCHK if we went in that
direction.  He also suggested that if the programs were kept separate, IBISCHK should
directly run TSCHK2 for Touchstone files and ISSCHK for IBIS-ISS files, and ISSCHK
should also run TSCHK2 for Touchstone files that it encounters.  An alternative to
embedding ISSCHK into IBISCHK would be to have ISSCHK print the number of terminals for
each subckt as INFO, which IBISCHK could read and use for checking.  Bob felt that it
might print too many such INFO lines. Mike suggested having a command line option to
enable it.  Mike added "Command option to print number of terminals for each subckt
(INFO)" as a level 4 option. He noted that it could easily be a level 1 option, but
it seemed better to keep level 1 simple.

Lance Wang asked if we might get permission to use HSPICE source code. Mike said Synopsys
had been asked and had declined.  Lance said other SPICE codes were capable of reading
HSPICE, maybe one of those could be used.  Mike noted that Atul had mentioned Berkeley
SPICE 3F in that context. We were not sure about the capabilities or licensing issues
that might arise.


Lance Wang moved to adjourn. Bob Ross seconded. Without objection the meeting ended.

Meeting ended: 12:05 ET

Next meeting August 27, 2019