================================================================================ 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 March 28, 2018 Meeting (* means attended at least using audio) ANSYS Curtis Clark Cadence Design Systems Bradley Brim Intel Corp. Michael Mirmak* Keysight Technologies Radek Biernacki Mentor, A Siemens Business Arpad Muranyi* Micron Technology Justin Butterfield, Randy Wolff* SiSoft Walter Katz*, Mike LaBonte* Teraspeed Labs Bob Ross* Michael Mirmak convened the meeting. No patents were declared. Randy Wolff took minutes. Review of Minutes: - Michael called for review of the minutes from the March 21 meeting. Arpad Muranyi moved to approve the minutes. Mike LaBonte seconded. The minutes were approved without objection. Review of ARs: - Arpad to fix the ground based drawing and send out the updated slides - This was done after the meeting last week. Arpad also reorganized the slides so the text from Walter's email was shown in the slides next to each drawing. Opens: - Michael noted the main agenda item is to continue the A_gnd question. Bob asked which draft version is the latest. Michael noted he has draft 18 version 4. Summary of ATM: Michael asked if we have any changes that need to be made to A_gnd after the last couple of weeks of discussion. Bob noted we are not making functional changes, just nomenclature. Arpad said we need to decide if we want A_gnd to be a local or global reference node. Bob asked what the difference is between node 0 locally or globally. Arpad noted there is no such thing as a node 0 locally if 0 is a global ground. Walter repeated his motion from email that A_gnd is to be interpreted as a simulator global ground equivalent to SPICE node 0. Bob asked if we need the word simulator. Walter thinks that word is necessary. This changes language describing A_gnd from "local" to "simulator global". Bob seconded the motion. There were no objections. Arpad noted we should make text consistent, such as changing "A_gnd is a universal reference node" to "A_gnd is a simulator global reference node". A change is also needed to page 94 of A_gnd as a connection in IBIS to a VHDL port. Bob and Arpad will discuss the port versus node language of this section and make a recommendation [AR]. Other mentions of A_gnd as a local reference were removed from the Terminal_type section. The sentence "A_gnd is the simulator ground ..." was left in the Terminal_type section. The sentence "Important: When Terminal_type A_gnd is used then the A_gnd node shall be used as the reference node for the I/O signal port(s) associated with the Interconnect Model" was discussed. Arpad did not know what this means, since it excludes rail ports. Walter thought it does not make any sense either. Bob thought we should tag it for deletion but have Radek make his case for leaving it in. Another sentence talks about use of node 0 inside IBIS-ISS subcircuits, with the simulator assigning it to A_gnd. Arpad noted that this is supported. Walter noted that if you use node 0 inside IBIS-ISS, then you may not account for all currents to the proper reference. Walter thought the sentence should be word-smithed to indicate why using node 0 is dangerous for power aware simulation. Arpad thought this sentence is not related to this issue. Arpad noted he asked Radek once before why a node 0 inside a subcircuit should be treated as A_gnd, which might be a local reference in the old context. Radek should explain this sentence, and it may need to be deleted. Walter noted that in documents supporting the BIRD, explanations of ground usage could be included. Two paragraphs were written by Arpad to make consistency between BIRD158 and BIRD189 regarding references between the models. Arpad asked for the two paragraphs to be marked to be rewritten. He will review the paragraphs for inclusion in BIRD189 [AR]. Walter thought the paragraphs should be excluded and put in supporting documentation. In Example 13, Randy requested that "vss" be changed to "VSS". Bob wanted to look further at the context of this labeling. Michael made changes to add "simulator global reference" to the example. Bob noted that use of A_gnd in Figure XX2 is correct. Walter asked Michael to search for the text "local". Three mentions of local were ok. Walter asked what is left to review. Arpad noted that there is discussion over rail relaxation rules from Bob needed. Michael will send out draft 18 v5 to the reflector. Next Meeting: The next meeting will be April 4. Task List BIRD189.5 editorial additions/changes to be completed: