================================================================================ IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ================================================================================ Attendees from May 5, 2023 Meeting (* means attended at least using audio) ANSYS Curtis Clark Intel Corp. Michael Mirmak* Michael Brownell Keysight Technologies Ming Yan Marvell Steve Parker MathWorks Walter Katz* Micron Technology Justin Butterfield Siemens EDA Arpad Muranyi*, Randy Wolff* ST Microelectronics Aurora Sanna Teraspeed Labs Bob Ross* University of Illinois Jose Schutt-Aine Zuken USA Lance Wang* Michael Mirmak convened the meeting and took minutes. No patents were declared. Michael called for review of the April 19 minutes and displayed them. He asked whether the team would be more comfortable with holding an approval vote on the minutes in the next meeting, given the minimal review time provided. He noted a typographical issue: a double-period at the end of one sentence. Arpad Muranyi moved to approve the minutes with the double period removed. Bob Ross seconded. The minutes were approved without objection. Michael reviewed the previous ARs - the only one outstanding was to Arpad, to send out the latest TSIRD5 draft, which he completed. Randy Wolff noted that the Touchstone history documents from Keysight Techologies were not discussed in the previous Open Forum meeting. Michael replied that the Open Forum needs to review the copyright statement from Keysight before posting the documents. Randy suggested placing them with historical Touchstone documents, or even keeping them in a private archive for historical use by the board. Michael reviewed the document requirements as he understood them. Arpad stated that the purpose of having these documents is not to "go backwards" in terms of support of older Touchstone features, but instead to have the original format that might still be supported by industry tools. Randy expressed doubt that anyone in the Open Forum will have a strong opinion about how and where to post the documents. The effort probably only requires a readme/text notice in a separate location on the website. [AR] Michael took the AR to talk to Steven Parker regarding options for posting the documents. Michael briefly mentioned Stephen Peters' response to his queries regarding the draft Touchstone 1.1 file. Stephen did not have previous documents and confirmed that no approval vote was ever conducted for the draft. Arpad reviewed draft 3 of TSIRD5 for editing. Bob noted that the changes he is proposing should be associated with Touchstone Version 2.1 and above. Randy asked whether there is already a requirement that if you have a [Version] 2.1 file and above, you must have as many entries on the impedance portion of the options line as ports? With this new multiple-R option line, we might want to enforce in the parser that the values in the option line match the values in the [Reference] keyword for 2.1. Bob replied that the R n n n syntax is supported in 2.0. Arpad stated that the document text says that, if [Reference] is present, it shall contain a reference for every port represented in the data. Does [Reference] have to match the contents of the # line? Bob replied that they must match. Randy noted that he did not know if the one-port situation is checked by the parser. Arpad shared the existing specification, which contains a strong implication that [Reference] overrides the options line in all cases. Randy added that, after checking the one-port case, the parser doesn't check for matching. Do we need therefore to require a check if values don't match? It's perhaps a don't-care situation if the option line and [Reference] don't match. Bob stated that, for 2.1, we should make a new rule that values in [Reference] match those for the option line, for all values. Arpad noted that the rules in TSIRD5 already clarified that the override is of the entire line. Randy added that the override makes the precedence clear. This could be more of a question whether the parser should look for a mismatch, which could be a caution-like behavior. Bob countered that, no, the file contents could be incorrectly generated without matching being enforced. Michael mentioned an historical counterfactual: the option line was required in 2.0 for permissive parsers of 1.0 syntax that we have never seen (meaning, for parsers that could read 2.0 files and ignore the new bracket-based syntax). Walter stated that the group was "going in circles" about [Version]. The industry does not care about 1.0 or 1.1; we have a new parser, which we could call 2.x. These are the new rules for parsing not-2.0 files and those which are 2.0. He prefers word "precedence" and not "override". Arpad replied that model-makers will not want to duplicate [Reference] keyword entries on the option line. Randy noted that people creating files automatically will ensure their automatic model writer matches both. Walter added that, if the values don't match, it's confusing what to do. Arpad suggested the rule should be to make them the same; if [Reference] has multiple entries and the option line has one, what happens? Bob answered that the choices are either to override or issue an error. The discussion continued, focusing on whether to enforce overrides for the single-port case. Michael noted that the version limitation is to avoid requiring 2.1 and the [Version] keyword for existing 1.0 files with multiple references. Bob added that we need 1.1 syntax. Randy suggested adding a section called "Rules for Version 1.1 Files:" with relevant language where needed. Michael asked whether the team wanted to add this to the TSIRD, and edit the entire document to include this or not. To add it will be painful. Randy stated that this will be handled in Editorial. Bob replied that he doesn't want to entertain these discussions in Editorial again. Walter asked whether we are documenting the 1.0 specification or 1.1 parser. Bob replied that we are not documenting the parser, we are documenting the specification. Arpad will write the relevant changes to the TSIRD draft for discussion next time. Bob added that he may introduce a TSIRD6 that shows his vision of how this works. The team agreed to cancel the next meeting for May 10, as it conflicts with the IBIS Summit in Aveiro. Randy moved to adjourn. Arpad seconded. The meeting adjourned. Next Meeting: The next meeting will be May 17, 2023 unless cancelled. ================================================================================ Bin List: 1. Draft Touchstone document separating version 1.0 and 2.0 2. Encapsulating Touchstone 1.0 data 3. Touchstone 2.0 draft with TSIRD3 and TSIRD4 4. Pole-residue format 5. Port naming 6. Alternatives to the Touchstone 1.0 option line 7. Enable Cascading of S-parameters Through W-element 8. Touchstone 3.0 draft outline (dependent on several items above) Tabled ARs: - Arpad to give an example of the physical connectivity needed for EMD automation.