================================================================================ 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 November 15 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 November 8 meeting. Randy Wolff moved to approve the minutes. Bob Ross seconded. The minutes were approved without objection. Review of ARs: - Arpad Muranyi to work with Bob and Walter on Sets and Groups language. - Bob reported this is still an open issue. Opens: - Michael noted he did receive some comments in an email from Radek on the File_TS0 and File_TS issue. He will ask Radek if those comments can be sent out the reflector [AR]. Summary of ATM: - Arpad summarized that Radek pointed out a problem with how the reference is connected to File_TS0 and File_TS. Arpad thought this problem includes existing IBIS structures such as [Pullup] and [Pulldown]. Randy stated there was an email from Radek on the issue, and Radek's suggestion is to add a warning to avoid these situations. Bob thought we can add cautionary language to warn against mixing references. Michael stated that Radek's email to him stated that having a component's terminal somewhere outside the model span is ambiguous. Radek had suggested to be specific about restrictions on Touchstone. Arpad stated that it is required to have node 0 somewhere in a simulation. Walter Katz commented that we are wrapping how models are done today. Bob stated that if you start mixing references you could get different results in different simulators. There is no change that we can make to the syntax to solve the issue. We can only add a warning for model makers. Michael asked if Radek has sent his recommended text. Bob replied he has not seen it. He stated that Radek's statement about no current flow into the reference is not an actionable statement. Michael stated the File_TS0 and File_TS referencing warning language should be added to the list of editorial changes to be made to BIRD189.5. IBIS-ISS should not declare terminals as "reference": Arpad stated that the word "reference" could be confusing, since for IBIS-ISS, it has no special meaning. While, for touchstone, we have special meaning for the word "reference". Bob agreed that this is a good idea, and in the examples, the reference nodes are just like the other nodes. He thought we can simply remove the word "reference" from the IBIS-ISS examples. Michael asked if anyone was opposed to removing the word "reference" from the IBIS-ISS examples. No objections were raised. Groups and Sets: Michael asked if the Groups and Sets issue was resolved in ATM. Bob said that it was not. Bob commented that we can only have terminals at two of the three boundaries. Walter noted that in any interconnect model you can have buffers and pads, buffers and pins, and pads and pins. He thought this is well stated in BIRD189.5. Bob stated that for interconnect model sets we have the same boundaries. Arpad commented that there is a statement in BIRD189.5 that the Interconnect Model Set must be complete. Walter noted if you take all the models in a Group, then there should be some rules on those models. You cannot have an Interconnect Model from pin to buffer and pin to pad on the same pin name. Walter had sent an email asking if we want to support die only cases (buffer to pad) and if we want to support pin to pad only interconnect models. Walter thought it should be legal to have buffer to pad interconnect model only and not from pad to pin in a Group. We should also support pin to pad only connections where the on die interconnect is assumed to be included in the [Model]. Bob commented that with respect to Groups there are additional considerations. We must consider PDN and signal paths. It is possible that the pad terminals may be different than the buffer terminals. He noted that we should be very specific in how to handle this. Bob would like to have 3 different Group keywords to describe the different cases for buffer to pin, buffer to pad, and pad to pin. He proposed to have an explicit terminal merging concept that could deal with all the combinations of the PDN connections. He noted that for stacked die, the pad names could be different from the pin names. Walter commented that stacked die would be handled with another syntax similar to EBD. Michael asked if we can add some changes to address Group and Set rules to our editorial bin list. Bob thought that we need to come to a resolution on what those changes should be first. Bob thought we need to be careful how these rules would be applied to the Set. Walter thought the rules should be applied to the Group, since it is the top level. He thought it does not make sense to force model makers to apply shorts in the Set when the model would be generated directly by an extraction tool. Walter noted that the EDA tool can look and determine what the interconnect model contains then decide where shorts are to be applied. Michael asked Walter and Bob to write concise statements of the rules for Interconnect Model Sets and Groups [AR]. Bob thought if we add shorts, we should make a rule to add a short for all missing cases. He would like a way to explicitly merge at the boundaries and remove the implicit shorts. Bob requested to add an additional discussion item to the agenda about rules for Aggressors. The next meeting is tentatively scheduled for Wednesday November 22. Michael volunteered to take the minutes. Walter moved to adjourn. Arpad seconded. The meeting adjourned without objection. BIRD189.5 editorial additions/changes to be completed: 1. File_TS0 and File_TS referencing warning language. 2. Remove the word "reference" from the IBIS-ISS examples.