IBIS Macromodel Task Group Meeting date: 06 July 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 Kellee Crisafulli, Celsionix 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: - None -------------------------- Call for patent disclosure: - No one declared a patent. ------------- Review of ARs: - Arpad eliminate TTT case from AMI flows. - 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: 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: IBIS Interconnect SPICE doc: - Arpad sent some comments to MM - For example, dollar sign comment char at beginning of line not allowed - MM: Need to clarify "string" concerns - Arpad: We probably want to support things like file name param values - MM: Most significant changes have already been made Arpad showed the latest AMI Flow #9 slides: - Slide 8 significantly reduced - Eliminating TTT case reduced down to 4 equations - Slide 1: Only slide for statistical simulation - Slide 2: Only boolean is GetWave_Exists - Slide 3-5: Avoids deconvolution - All requests incorporated - Ken: This is much simpler - Slide 3 is just for Tx Init+GetWave + Rx Init-only case? - Arpad: The optimizer needs to know what Tx Init is doing - Ken: Is Tx GetWave needed at all? - Walter: Tap coefficients don't change - Tx Init output is LTI and therefore pattern-independent - Tx models have up to 16 tap FIR filters - Init representation relatively good - But they do have pattern dependencies (DCD) - Tx GetWave takes care of those - Fangyi: Doesn't the simulator add jitter? - Walter: A simulator can't handle data path dependent jitter - It depends of the bit pattern - Fangyi: Are these chip to chip differences? - Walter: It is part of the buffer - Todd: Tx GetWave is problematic with analog input - Can only do LTI until we have digital input - Ken: This supports advanced jitter capabilities - Fangyi: So this is for jitter and also for FIR filter - MM: Is the Tx EQ issue a limit of IBIS AMI or the industry - Walter: Industry - Ken: There will be an advanced jitter BIRD anyway - We could take out Rx optimization now - Arpad showed slide 5 - Walter: This is a classic Rx buffer with self-adapting DFE - A long enough sim will converge the Rx model (100k to 1million bits) - It would be nice to initialize tap coeffs so that less bits are needed - Only way is by passing best guess to Rx Init - Then Rx GetWave will converge quickly - Need an accurate Rx Init_Returns_Filter - Todd: We were trying to avoid deconvolution at Arpad's suggestion - If we leave that behind the flow diagrams become very simple - It is instructive to see it that way - Arpad: The dual matrix was also needed for optimization - Without deconvolution the flow for TD and statistical could be the same - Fangyi: In statistical the bit pattern goes to Rx GetWave - In TD the bit pattern goes to Tx GetWave - Arpad: In statistical we don't convolve - Fangyi: Effectively it is - Walter: You can make a good Hre approximation for DFE - A DFE is LTI under some circumstances - Todd: It is a linear approximation - Walter: No way to get just the Rx filter in the current system - Deconvolution can do that if we accept it - We don't have to add another parameter - It is debatable whether this is a legal enhancement - We can have a scheme where existing models and flows will work - Kumar and I are not concerned about deconvolution - Fangyi: The LTI model will not operate in cascade fashion - Todd: That is a contradiction - Fangyi: The impulse responses are not necessarily connected to the filter - Todd: There has to be a linear relationship between two impulse responses - Walter: If it is LTI you can go back and forth between domains - Todd: We started trying to avoid deconvolution - We have not reduced this to the essentials - What set of flows are we trying to describe? - I would like to present next week - Ken: Maybe the optimizer part should be moved to the jitter BIRD - Todd: That can be addressed - Dropping Use_Init_Output made it more elegant - Walter: There is no longer a jitter BIRD - Arpad: If we take out out some cases will not work - Walter: We would only have to accept that deprecation is necessary - Arpad: We are going in circles - We need to end this somehow Todd will present next week Next meeting: 13 July 2010 12:00pm PT -------- IBIS Interconnect SPICE Wish List: 1) Simulator directives