====================================================================== 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 September 14 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 Graphics 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. Review of Minutes: Michael called for review of the minutes from the September 7 meeting. Mike moved to approve the minutes. Bob seconded. The minutes were approved without objection. Review of ARs: Opens: Michael noted that the only major item on the agenda is the review of draft 39. Bob added that a future agenda item is dealing with ground and power nets referencing. Although, he said he was not prepared to discuss it in this meeting. Michael asked if we want to include this as part of Interconnect BIRD. Bob pointed out Walter's comment last time that the decision on how to handle the reference should be up to the model makers. But, he thought we should discuss it and make a recommendation. Michael mentioned we should go over the ARs from last time. We had the discussion on page 43 about the [Receiver Threshold] referencing. He mentioned that he is working on a BIRD to clarify that section. And, he asked Mike if he still wanted to look into the Vcross_low and Vcross_high issue. Mike commented that the Vcross_low and Vcross_high are in the [Receiver Threshold] section. He also brought up that Vth is the voltage that the other thresholds are relative to. Walter added the Reference_supply subparameter is the reference for Vth. He also noted that that we can think of the [Pulldown Reference] as the local ground for a [Model]. The difference between the Reference_supply voltage and the Vth value sets the offset to the other [Receiver Threshold] subparameters. Walter commented that the Vcross_low and Vcross_high are not referenced to a supply, and the 0V is just a number not a measurement. The measurement is between the negative and positive pins of the differential signal. The sentences regarding Vcross_low/Vcross_high being with respect to 0V could possibly be removed. Bob clarified that Vcross_low and Vcross_high are the absolute limits of the crossing voltages. These are the single ended limits for the crossing point voltages. Mike asked if this issue should be discussed here or in ATM or Editorial. Michael agreed we should consider moving the discussion and asked if we want to separate this from the [Receiver threshold] BIRD. Walter thought it should move to the ATM group. And agreed with Bob that Vcross_low/Vcross_high look at the common mode signals with respect to ground. He also thought it should be clarified in a separate BIRD. Michael stated that if there were no objections, the discussion would be moved to the ATM group. No objections were stated. Interconnect BIRD draft 39 Review: Michael stated that the last comment we reviewed was the comment #6 in draft 39. The document review resumed on page 4 in the [Interconnect Model Set Selector] section. Mike mentioned that he had started a draft 40, which had incorporated some of the suggested changes. Michael suggested to use that version to make edits. Interconnect BIRD draft 40 Review: Mike noted that the change from .ict to .ims is not in this draft yet. He did add some brackets to keywords in the text of the draft. Michael commented that if we are referring to the concept, then we do not need to use the brackets. But, when we refer to the keyword, then we should use the brackets. Mike stated that he did add the forward reference text that Bob had requested. Michael asked about the issue with using *.ibs when the [Interconnect Model Set] is defined in the IBIS file. He noted that in our August 31 meeting Walter gave three options that included: *.ibs, NA, or blank. Arpad also suggested a to use "In line". Bob commented that he did not like "In line", and he prefers the *.ibs. We could use blank, but that is not a good convention, since the parser expects an entry in this field. Michael commented that a single word entry would be better. Bob commented that we use NA for missing data. Mike commented that we have used NA where a value could have been, and he doesn't see an issue with using NA. Walter made a motion to use NA when the [Interconnect Model Set] is defined in the IBIS file. Bob seconded. There were no objections. Bob noted that it should be made clear, when we have conflicting [Interconnect Model Set] names, that the one in the the IBIS file should be made the default. Michael thought that we need to discuss it. He asked what happens if the model is defined both in the IBIS file and externally. Mike suggested to add a simple rule that no [Interconnect Model Set] name should be duplicated. Walter agreed and commented not forcing them to be unique could be dangerous if there are conflicts. He suggested that we start out being more restrictive and can change it later. Walter made a motion that all the [Interconnect Model Set] names within an [Interconnect Model Set Selector] must be unique. Bob seconded. There were no objections. Bob commented that the examples need to be cleaned up and possibly shortened. He also suggested to to improve some of the example names for consistency and readability. Walter suggested to remove the comments in the draft as we resolve the issues. We can review the comments off-line to get through the document more efficiently. Mike asked about the first sentence in the last paragraph on page 4, in regards to the first entry in the [Interconnect Model Set Selector] being the default. He suggested to remove this sentence, noting that it is up to the EDA tool to determine which pins are needed. The first set in the list may or may not contain the necessary pins. Walter made a motion that to strike this sentence ("The first entry under the [Interconnect Model Set Selector] keyword shall be considered the default by the EDA tool.") from the document. Randy seconded. There were no objections. Walter commented that he will write an email going through each comment in the document and make a recommendation on each one. Some can be deleted while others might need some discussion. Bob added that we might want to add more new comments to the draft. Mike stated that he will post the current revision as draft 40. Mike moved to adjourn. Walter seconded. The meeting adjourned without objection.