IBIS Macromodel Task Group Meeting date: 13 April 2010 Members (asterisk for those attending): Adge Hawes, IBM * Ambrish Varma, Cadence Design Systems Anders Ekholm, Ericsson * Arpad Muranyi, Mentor Graphics Corp. Barry Katz, SiSoft * Bob Ross, Teraspeed Consulting Group Brad Brim, Sigrity Brad Griffin, Cadence Design Systems Chris Herrick, Ansoft Chris McGrath, Synopsys * Danil Kirsanov, Ansoft David Banas, Xilinx Deepak Ramaswany, Ansoft Donald Telian, consultant Doug White, Cisco Systems Eckhard Lenski, Nokia-Siemens Networks Eckhard Miersch, Sigrity Essaid Bensoudane, ST Microelectronics * Fangyi Rao, Agilent Ganesh Narayanaswamy, ST Micro Gang Kang, Sigrity Hemant Shah, Cadence Design Systems Ian Dodd, consultant Jerry Chuang, Xilinx Joe Abler, IBM John Angulo, Mentor Graphics John Shields, Mentor Graphics * Ken Willis, Sigrity Kumar Keshavan, Sigrity Lance Wang, Cadence Design Systems Luis Boluna, Cisco Systems * Michael Mirmak, Intel Corp. Mike LaBonte, Cisco Systems Mike Steinberger, SiSoft Mustansir Fanaswalla, Xilinx Patrick O'Halloran, Tiburon Design Automation Paul Fernando, NCSU Pavani Jella, TI Radek Biernacki, Agilent (EESof) * Randy Wolff, Micron Technology Ray Komow, Cadence Design Systems Richard Mellitz, Intel Richard Ward, Texas Instruments Samuel Mertens, Ansoft Sam Chitwood, Sigrity Sanjeev Gupta, Agilent * Scott McMorrow, Teraspeed Consulting Group Shangli Wu, Cadence Design Systems Sid Singh, Extreme Networks Stephen Scearce, Cisco Systems Steve Kaufer, Mentor Graphics Steve Pytel, Ansoft Syed Huq, Cisco Systems Syed Sadeghi, ST Micro Ted Mido, Synopsys Terry Jernberg, Cadence Design Systems * Todd Westerhoff, SiSoft * Vladimir Dmitriev-Zdorov, Mentor Graphics Vikas Gupta, Xilinx Vuk Borich, Agilent * Walter Katz, SiSoft Wenyi Jin, LSI Logic Zhen Mu, Mentor Graphics ------------------------------------------------------------------------ Opens: - Michael Mirmak: Did we decide on a uniform list of tool/IC vendors supporting AMI? Arpad: tool vendors will do their own announcements. Walter: Is there a place on IBIS website for those who support IBIS? Michael: Model library is a comprehensive list. Bob: Roster page also lets companies show how they support IBIS. Walter: Thinks this is the appropriate place for that. -------------------------- Call for patent disclosure: - No one declared a patent. ------------- Review of ARs: - Arpad: send the two BIRD documents and updated spreadsheet to Mike L. to be posted - done - Arpad: Write parameter passing syntax proposal (BIRD draft) for *-AMS models in IBIS that is consistent with the parameter passing syntax of the AMI models - TBD - TBD: Propose a parameter passing syntax for the SPICE - [External ...] also? - TBD - Arpad: Review the documentation (annotation) in the macro libraries. - Deferred until a demand arises or we have nothing else to do ------------- New Discussion: 1. Discuss updated Task List spreadsheet Arpad: Groups of items in the spreadsheet are parser developer questions, AMI flow related, and ambiguities in the text. Arpad: Under scale factors, what is 'clarify AMI is a control/initialization syntax'? - Bob: Just that AMI should not support scale factors. Arpad: Under white space, is CRLF allowed in .ami files or parameter strings extracted from it? - Bob: In .ami file, anything is allowed by the parser. - Michael M: The .ami section of the spec covers this maybe, but it isn't clear if it describes what is allowed in the parameter string for the DLL extracted from it. - Arpad: Parameter strings are a separate topic. Arpad: Will take offline questions on lines 17 to 23. 2. Discuss AMI Flow BIRD Arpad: Ken Willis, Ambrish, and Fangyi all sent emails to the reflector related to the Init_Returns_Filter boolean. They were in opposition to including this in the current Flow clarification. Arpad showed a flow without this boolean. He found issues when both Tx_GetWave and Rx_GetWave exist. - Ambrish: You can use the flow in the current spec. - Arpad: Same issue with Tx_GetWave only. Ambrish: Slide 6 is a special case. We won't expect an equalization in the Init call and GetWave at the same time. - Arpad: The boolean is appropriate in this case. Either we don't support this case at all or we support the boolean. - Ambrish: Might be another way of doing this that Kumar discussed. The tool generates a unit impulse response. Arpad: Making any changes will take another month at least to approve. We need to decide today whether to make more changes or go with the flow decided last year. - Fangyi: Before we were talking about a new spec. Now we are talking about a cleanup only. We can introduce this in a new version of the standard, but not in a cleanup BIRD. - Arpad: But is it worth our time to create two separate BIRDs on the flow? - Ambrish: Adding this boolean makes the flow a lot more complex. - Fangyi: Adding this boolean doesn't fix current models, that is why it is a new feature. Arpad: Change plan on voting on the BIRD and instead vote on whether we keep the BIRD as it is (Yes) or whether we create a separate cleanup BIRD (No). Vote results: Ambrish No Arpad Yes Bob Abstain Danil Yes Fangyi No Ken No Michael No Randy Abstain Todd Yes Arpad: With a No vote, he will prepare a new flow for next week that satisfies the existing clarification flow as well as the new flow. - Fangyi: All the analysis of different scenarios is still valid for the new flow. 3. Clock_times BIRD discussion Arpad: Showed a difference view between the old and new clock_times description in the specification. - Scott: Main difference is redefinition of period to be the instantaneous period. One interpretation means the nominal UI of the bit stream, but physical device doesn't care about that. This is incorrect and can give the wrong results when we look at the sampled point and the clock from the CDR. Scott: This BIRD defines what a clock_time is and what it means. It eliminates anomalies found in current models. Clocks must be monotonic. A pair of values in the clock time array are used to derive the instantaneous sample point, not an average sample point. - Fangyi: What if there is a missing clock tick? He remembers in current spec that there could be a missing tick. - Scott: The tick is a physical sampling point in time. - Vladimir: There is confusion between two things. Number of clock ticks could be different from number of samples. Once all GetWaves are combined, there should be no missing times. - Scott: if a CDR failure occurs, goes out of lock, you get longer or shorter intervals. This is ok. Scott: Clock times are the transition edge of the phase lock clock. Second statement says that sample is assumed to occur half a clock period after that. One can make it either nominal or the instantaneous clock time. If nominal, in a CDR system, if sending back the phase locked clock and if not a nominal period, EDA platform computes the wrong sample point. - Fangyi: Model makers are concerned about where the clock is centered, not where it is sampled. - Scott: The only important thing to the EDA platform is where the sample point is, but it isn't being returned. - Walter: AMI modeling system is similar to IBM's HSSCDR. It outputs the waveform and where the location is being sampled. The clock ticks are meant to be related to 1/2 the nominal UI period. The spec says "one half clock period" but should be one half bit time. - Scott: will re-write the spec to indicate that clock times are calculated based on the internal sample point corrected by 1/2 the nominal UI. Vladimir: How can we distinguish? What should EDA tool do if clock times will appear after one million bit simulation. - Arpad: The issue is if a tool can distinguish between getting no clock times and getting clock times after a very long wait. This affects memory allocation. - Fangyi: You can prepare the eye when no clock ticks return using uniform clock ticks. If you get real clock ticks, then use them and throw out the uniform clock ticks. You have to assume the clock ticks relate to time zero when they do arrive. AR: Arpad to create new flow diagram for the clarification BIRD. AR: Scott to rewrite clock ticks BIRD Next meeting: 20 Apr 2010 12:00pm PT -------- IBIS Interconnect SPICE Wish List: 1) Simulator directives