============================================================================== IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ============================================================================== Attendees from November 12, 2025 Meeting (* means attended at least using audio) ANSYS Curtis Clark, Wei-hsing Huang, Juliano Mologni Arista Networks Jim Antonellis Broadcom James Church Chipletz Stephen Newberry Intel Corp. Michael Mirmak*, Xiaoning Ye Keysight Technologies Ming Yan Marvell Steve Parker MathWorks Walter Katz* Micron Technology Justin Butterfield Siemens EDA Weston Beal*, Arpad Muranyi*, Randy Wolff* Simberian Yuriy Shlepnev ST Microelectronics Aurora Sanna Synopsys Ted Mido, Edna Moreno University of Illinois Jose Schutt-Aine ============================================================================== Michael Mirmak convened the meeting. No patents were declared. Michael had sent the October 29 meeting minutes to the reflector earlier; these will be reviewed in the next meeting. Similarly, the October 15 meeting minutes have not yet been sent out for review. Michael reviewed the latest draft, number 20, of the Port Mapping proposal for Touchstone 3.0, pointing out new explanatory text differentiating between node- oriented and pair-oriented parameters. He noted that some of the name-value examples later in the document were confused on how these should be used, in that concepts were not unambiguously applied. He pointed out that Reference did not always map clearly to names used for Logical (e.g., DQ5-). Weston Beal suggested that, for the relevant examples, Logical DQ5- should not be the negative terminal of the port. Walter Katz added that, in that example, the reference for port 3 is not port 4; the only useful +/- distinction is Physical. It is therefore not necessary to put the + symbol in. The - symbol for Physical is OK, but a + Physical notation makes no sense. Weston agreed, suggesting that Logical is still useful. The Reference in the transistor examples is likely Vss. Walter proposed that the - symbol should be limited to Physical and maybe Logical. Michael asked whether, for the examples, we should use Logical-only cases. Walter replied that defining a "Reference_Logical" would be acceptable. Randy Wolff noted that, in the explanatory text, "node" is a new word in this context, but "terminal" is not. These should be clearly defined and used consistently with other documents (IBIS, Touchstone). Arpad Muranyi suggested that subcircuits have terminals. Randy added that "node" is not a term used in IBIS. Arpad replied that batteries have two "terminals", each of which can be connected to many other circuits. A terminal becomes a node when connected to something else. Walter suggested that an electrical circuit is actually a mathematical graph. A battery has two nodes. An S-parameter can have N, N+1 or 2N nodes. Michael accepted the AR to verify the "terminal" and "node" language used in IBIS and Touchstone today. [AR] Michael noted that the terminal count that the parser or an EDA tool could calculate would be derived from the Logical and/or Physical entries. Walter replied that all this depends on how you are connecting the data to the rest of the circuit. Yes, you would have to hook up a reference node to the Emitter circuit in the Emitter-referenced example shown (unless you know how it is being used). Weston suggested that the document does not feature good examples because Logical maps to Physical. But a co-planar probe has a Reference with *two* physical points. This doesn't map clearly between Logical and Physical. Randy stated that, for Physical cases, you have labels on physical structures (Walter added that an XY location can also be used). Logical is used when you don't have any physical information. The team discussed how parsing rules would be developed and applied. Addition of Reference_Logical, Reference_Physical parameters was discussed. Randy suggested that "Reference_Side" and "Reference_Type" should not be supported. Weston proposed that "Reference_Net" be added, as the concept is needed. Randy replied that the proposal still contains "Group" for this purpose. Michael pointed out Examples 3a and 3b already use this. Walter added that Reference is assumed for Group to be Physical; otherwise we can use Reference_Physical. Randy pointed out that Example 4 uses a Physical reference; Example 3b is almost something new. Arpad asked whether a "Reference_Group" term should be defined. Walter replied that Group is simply another way of declaring a pin; Randy suggested a correction, that it is a declaration of a *group* of pins. Walter replied that "Group" is a list of pins, not a single pin declaration. Weston asked what the types allowed for Groups are. Randy replied that only Physical pin declaration should be allowed for Groups; Weston agreed. Arpad noted that Group is used for VDD as well. Michael added that Group is available for power or ground, just not for signals. Michael concluded that no "Reference_Diff_port" should be defined, and that there was no need for Reference variants of Side and Type. He then asked about Reference_Net. Arpad objected to the use of Reference_ as a prefix; he expressed a preference for the - symbol. Weston noted that, if we have each word in parentheses with its own argument, expanding the syntax is fairly easy. With the - symbol, each name can only have one value which we have defined now, but may be non-extensible. Arpad suggested that the same rules should apply for the + and - symbols. Michael noted that Diff_port and +/- are different concepts. These should not interact. Arpad clarified that he was not advocating for requiring + in all cases, though using it makes the syntax more clear and unambiguous. The original proposal for port mapping used + optionally, but - was required. Weston replied that he would require it. Walter agreed with Arpad that + can be optional. Michael will attempt to update the draft to address these suggested changes. Arpad moved to adjourn the meeting; Randy and Weston seconded. The meeting adjourned without objection. ==============================================================================