=============================================================================== IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ================================================================================ Attendees from June 3, 2024 Meeting (* means attended at least using audio) ANSYS Curtis Clark, Juliano Mologni Broadcom James Church Intel Corp. Michael Mirmak* [Michael Brownell] Keysight Technologies Ming Yan Marvell Steve Parker MathWorks Walter Katz* Micron Technology Justin Butterfield Siemens EDA Weston Beal, Arpad Muranyi*, Randy Wolff* ST Microelectronics Aurora Sanna Synopsys Ted Mido, Edna Moreno Teraspeed Labs [Bob Ross] University of Illinois Jose Schutt-Aine Zuken USA Lance Wang Michael Mirmak called the meeting to order. No patents were declared. An attempt was made to record and transcribe the meeting, but this failed due to lack of permissions. Michael took the AR to contact Tammy at SAE-ITC on transcription rights. [AR] Michael shared the minutes of the May 22 meeting for review. Arpad Muranyi moved to approve the minutes; Walter Katz seconded. The minutes were approved without objection. Michael noted that his AR was closed regarding contacting Eric Bogatin, Scott McMorrow and Donald Telian regarding the port-mapping proposal features. All three had been contacted; two had responded. Michael will provide a summary when responses had been received from all three. Walter suggested also contacting Dr. Yuriy Shlepnev. Michael accepted this AR. [AR] Michael shared the minutes of the May 22 meeting for review. Arpad Muranyi noted that the minutes referred to a issue involving a potential conflict between Touchstone and IEEE 2401. In fact, the potential problem was with series capacitance and IEEE 370 was being referred to. Michael agreed this was an error. Arpad proposed removing the following statement from the minutes: "Arpad suggested there may be a conflict between Touchstone mapping and IEEE 2401 mapping if, for example, capacitance netlist information is defined in the Touchstone file but is used in multiple instances." Michael noted that he will send a proposed update to the language as a response to Arpad's e-mail reflector post. Arpad moved to approve the minutes with this change; Walter seconded. The minutes were approved without objection. As a separate effort, Arpad noted that he had created a list of keywords from IEEE 370 as a single page Microsoft* Word document. He noted the high degree of similarity between the keywords there and the Touchstone 3.0 proposal. Michael accepted the AR to ask Xiaoning Ye of the IEEE 370 team to participate in the Interconnect meeting. [AR] Michael also accepted the AR to send the updated port-mapping priority list to the reflector for comment. [AR] Arpad showed his summary of IEEE 370 keywords. Some inconsistency was noted in the use of keyword brackets. Some keywords, such as [Manufacturer] are similar to IBIS. Pin and port mapping approaches are different than our proposals for Touchstone 3.0. No mention is made of reference terminals; just ports and pins. There is a different approach focused on the measurement environment. Walter added that IEEE 370 was focused on SerDes, not on DDR with multidrop topologies. It assumes all connections are two-port, and also assumes a particular schematic symbol arrangement. Michael responded that there is no connectivity challenge there either. Walter suggested this was an overlap of functionality. We should be able to easily convert from their format to ours. In addition, Touchstone 3.0 should require that IEEE 370 be auto-converted to Touchstone 3.0 format. We should also use their keywords. Michael asked whether the team should add a priority item pulling in the IEEE 370 keywords. Arpad replied that we should, if they are willing to work with us; we don't want two independent workgroups implementing similar concepts and keywords. Michael additionally asked whether the features in IEEE 370 related to measurement, comments, and an extension to non-SerDes be added. It would be good to understand their plans. Michael asked what the two proposals were missing, if anything, in comparison to the priority list, showing the latest copy. Port Mapping Proposal Requirements, in Priority Order 1) Define unambiguous connections for simulation o Declaration of differential ports, cord ports (not data) 2) Support generation & verification of: o [Interconnect Model]s in .ibs files o [EMD Model]s in .emd files o [C Comp Model]s in .ibs files 3) Support automated creation of: o Schematic symbols o Test probe locations 4) Identify Port locations (e.g., xyLayer in PCB) 5) Support user-defined parameters (similar to IBIS AMI’s model-specific parameters) Other Touchstone 3.0 Requested Features 1) Support IEEE 370 data quality features (not through comments) – passivity, causality, reciprocity 2) Identify data status (port data is measured vs. port data is simulated-only) 3) Include simple indicator(s) of whether data represents interconnect, whether data is expected passive or not 4) Support swathing (e.g., for connector or cable descriptions) He suggested the "Other" list item #1 regarding data quality analysis features from IEEE 370 was still missing. Arpad asked whether the team was referring to more Touchstone 3.0 features beyond port mapping and compression. Walter asked why we want port mapping. What would cause people to switch from Touchstone 1.0? The answer is that Touchstone 2.0 didn't have the features we are being asked to add What would cause people to want to write Touchstone 3.0 files? He noted that we need to encourage EDA suppliers to both generate and read these models. Walter asked whether the "Other" item #2 referred to the entire file or a specific i,j element. Arpad suggested this might refer to the whole file. He asked whether people combine measured and simulated data. Walter and Michael agreed that this is done often. Walter suggested that "Sij" be used as a marker followed by i and j ranges indicating measurement. Walter further noted that swathing could be supported through a swathing schema in, for example, a connector file (which his employer has implemented). This could be put in a separate standard. Many different representations are possible. It could be useful to combine Touchstone 3.0 with a connector-swathing representation, using one keyword with the name of the schema. Michael noted that it may be too cluttered to support "Other" items #2 and #3 together with the port list. Arpad suggested it would not be too bad; Walter agreed but suggested they could be separate. He added that a Touchstone file is just a container of matrices; there could be a separate section or keyword within port mapping but not part of the main map. Arpad noted that the current proposals have a list of ports with attributes. Walter noted that measured vs. simulated as an indicator is not per-port but uses Sij. Arpad replied that this could use its own map. Walter proposed Sij as its own keyword, followed by 1:4 8:12 to indicate measured vs. simulated in a compressed way. For user-defined parameters, Walter noted that some characteristics users or data generators want to add are why this would be useful. Without it, the only option is to use comments or write some TSIRD to make the changes. Arpad replied that it would be hard to know what the data means, for automation. Walter replied that it may reduce re-coding by parser developers if the data source isn't available. Arpad suggested an approach similar to #define, type etc. in programming languages. Next time the team will review IEEE 370 features, plus may engage in a side-by-side comparison of the existing proposals. Arpad moved to adjourn; Walter seconded. The meeting adjourned without objection. The next meeting will take place on June 12, 2024. ================================================================================ Bin List: 1) [Complete draft Touchstone document separating version 1.0 and 2.0 into their own chapters] - REMOVED 2) Create structures to encapsulate Touchstone 1.0 data in Touchstone 2+ specifications - TABLED 3) Complete draft Touchstone 2.0 document containing TSIRD3 and TSIRD4 draft (Muranyi) – COMPLETED 4) Complete pole-residue format BIRD draft (Muranyi) - COMPLETED 5) Complete port naming proposal (Katz) - COMPLETED 6) Create alternatives to the Touchstone 1.0 option line before the "R" character - TABLED 7) Complete ISS-IRD 1 Draft - Enable Cascading of S-parameters Through W-element (Mirmak) - TABLED 8) Complete/revise Touchstone 3.0 draft outline (Mirmak) – dependent on several items above Tabled ARs: - Arpad to give an example of the physical connectivity needed for EMD automation.