================================================================================ IBIS INTERCONNECT TASK GROUP http://www.ibis.org/interconnect_wip/ Mailing list: ibis-interconnect@freelists.org Archives at http://www.freelists.org/archive/ibis-interconn/ ================================================================================ Attendees from October 4 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, Ming Yan Mentor, A Siemens Business 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 convened the meeting. No patents were declared. Justin Butterfield took minutes. Review of Minutes: - Michael called for review of the minutes from the September 27 meeting. Mike LaBonte moved to approve the minutes. Bob Ross seconded. The minutes were approved without objection. Review of ARs: - Michael to discuss the unused port issue with Radek. - Michael reported this is done. - Bob to send out BIRD189.5_draft9_v2 to e-mail list. - Bob reported this is done. - Radek Biernacki to send his questions to Arpad Muranyi to add to the ATM meeting agenda. - Michael stated that this can be considered closed. Opens: - Michael stated that we should summarize the discussion from the ATM meeting on the unused port termination. - Bob commented that we need to review the text after Table 41 and the examples to ensure we do not have any contradictory rules. Michael thought some of this can be part of the editorial review. Arpad suggested we should resolve the technical issues first before getting into to editorial issues. Unused port termination: Michael noted he sent out an email attempting to summarize the conclusions of the discussion in the ATM meeting. Arpad suggested that the unused port termination should only be required if the terminals are less than the ports. Bob thought there was general agreement that the specification should allow for open termination or terminated with the reference impedance. However, the syntax was not decided. He commented that the idea is to reduce the size of the matrix, and the unused port parameter would apply only to Touchstone. This would add additional rules that must be checked, and the examples would need to be changed. Michael asked if all of these rules are parsable. Bob replied that they are parsable rules. Bob stated he sent out a proposal for the new parameter calling it Reference_impedance_termination. It gives both choices of open or terminated. There would be a parsable advantage that all ports do not have to be counted. Other termination choices could be available from the EDA tool. Randy Wolff asked if it is required that Touchstone file names include the number of ports. Arpad replied this is not required. Bob clarified that Touchstone 2 has the number of ports parameter, while for Touchstone 1, the columns must be read. Michael asked who will make the changes based on what was decided in the ATM meeting. Bob had mentioned he would be willing to make these changes. He referenced the email he sent that included a proposal for the added text. Bob commented that the model maker only knows about the model and its reference impedance, but they do not know the application. Using the reference impedance for the unused port termination is an approximation. Arpad stated that he was previously thinking that there would be no reflections if the reference impedance is used to terminate, but this is not the case. There will typically be mismatches to the reference impedance, and there is no perfect solution for model reduction. Michael mentioned he would like Radek to review Bob's proposed text. Randy stated he likes Arpad's suggestion of when the unused port parameter should be present. Bob stated he is concerned about the development of the parser for these rules. Arpad moved to have Bob take an AR to put the unused port parameter in the BIRD. Bob seconded. There we no objections. Bob noted that this will be a lot work, and he has limited time. Arpad thought it might be good to add an example that uses the unused port parameter. Mike asked if Arpad would be willing to help Bob make the changes. Arpad said he could help and requested Bob to let him know how. Bob said he will add the unused port changes, but he would not yet go through the rest of the document looking for other changes. Michael amended Bob's AR to include help from Arpad. File_TS0 Additions: Michael stated he believes that the File_TS0 changes have been added to the latest draft. Bob confirmed these changes are in the draft with improvements from Arpad and himself. Arpad noted that there is the word "Terminal_line", but he thinks this is not an official parameter and suggested to remove the underscore. Bob agreed and said he will remove the underscore and change to lower-case. Michael stated we can close this issue for now. Selection Mechanism for Model Sets Arpad noted that this is not yet resolved. He and Walter Katz have discussed this, and they agreed that the only selection mechanism should be the [Interconnect Model Set]s, but there is no text in the BIRD to clarify this. Bob clarified the [Interconnect Model Set Group]s should be the selection mechanism. Walter commented that we want to make it illegal to have two [Interconnect Model]s that have the same pin in one group. However, he would like to qualify that this should only apply victims. Bob disagreed with this approach. Walter stated that this approach is important for the "swathing" modeling approach with few models for many pins. The aggressors can overlap in that case, and it is a legitimate use case for applications such as connectors. Mike emphasized that each pin should appear only once as a victim net. Bob stated that any pin that is not an aggressor is a victim, but we have no way of knowing what is inside the Interconnect Model. From a checkable syntax rule standpoint, duplicated pins and duplicated IO_buffer numbers in a group can create problems. The [Interconnect Model Set]s can include all the models as well as [Interconnect Model Set Group]s. Walter stated that when you select a group, it brings in the sets which brings in the models, and no two models can have the same victim pin. You can ignore pins that are aggressors. Michael asked Arpad if he would be willing to address these changes in the BIRD draft. Arpad said he would like to have a clean version to work with first. Mike suggested to post the latest version as an official draft. Bob stated that this would be the BIRD189.5_draft9_v3_cleanup1. Mike asked if this version has the unused port termination additions. Bob replied that it does not. Mike moved to post the BIRD189.5_draft9_v3_cleanup1 without the unused port termination edits as BIRD189.5_draft9 [AR]. Bob seconded. There were no objections. The next meeting will be on Wednesday October 11th. Mike moved to adjourn. Randy seconded. The meeting adjourned without objection.