IBIS Macromodel Task Group Meeting date: 07 May 2013 Members (asterisk for those attending): Agilent: * Fangyi Rao * Radek Biernacki Altera: * David Banas Julia Liu Hazlina Ramly Andrew Joy Consulting: Andy Joy ANSYS: Samuel Mertens * Dan Dvorscak * Curtis Clark Steve Pytel Luis Armenta Arrow Electronics: Ian Dodd Cadence Design Systems: Terry Jernberg * Ambrish Varma Feras Al-Hawari Brad Brim Kumar Keshavan Ken Willis Cavium Networks: Johann Nittmann Celsionix: Kellee Crisafulli Cisco Systems: Ashwin Vasudevan Syed Huq Ericsson: Anders Ekholm IBM: Greg Edlund Intel: Michael Mirmak Maxim Integrated Products: Mahbubul Bari Hassan Rafat Ron Olisar Mentor Graphics: John Angulo Zhen Mu * Arpad Muranyi Vladimir Dmitriev-Zdorov Micron Technology: * Randy Wolff Justin Butterfield NetLogic Microsystems: Ryan Couts Nokia-Siemens Networks: Eckhard Lenski QLogic Corp. James Zhou SiSoft: * Walter Katz * Todd Westerhoff Doug Burns * Mike LaBonte Snowbush IP: Marcus Van Ierssel ST Micro: Syed Sadeghi Teraspeed Consulting Group: Scott McMorrow * Bob Ross TI: Casey Morrison Alfred Chong Vitesse Semiconductor: Eric Sweetman Xilinx: Mustansir Fanaswalla Ray Anderson The meeting was led by Arpad Muranyi ------------------------------------------------------------------------ Opens: - Walter: Hope to discuss my email today -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Walter working on clearer flow document for Redrivers. - Walter to write new BIRD for [Repeater/Retimer Pin] keywords. - in progress ------------- New Discussion: No interconnect Task group report PI & SI simulations with legacy IBIS model - Arpad: Has draft 8 of Walter's BIRD been posted? - Walter: No - Walter: Power voltage far from that used for model derivation will cause inaccuracies - Arpad: The IBIS Data Derivation section does not require simulation at Pullup reference voltage - Walter: For legacy IBIS models, yes - For [External Model] no assumption can be made about how to handle other voltages - Arpad: It is not true that voltage should be between min and max, for example - We might need some editorial cleanup - Walter motioned to send this issue to the editorial committee - Bob seconded the motion - No one opposed BIRD 156 IBIS-AMI Extension for Mid-Channel Redriver - Arpad showed the email from Walter, which has 3 bullets: - 1) Only discusses TD simulation - Walter: Need to discuss this with Fangyi - Todd: We need to see how it fits with 10.2.1. and 10.2.2 in the existing spec - Fangyi: We assume the EDA tool can figure out statistical once the TD flow is known - I can add that to the BIRD - Bob: There is a different flow for redriver - Fangyi: The only difference is constructing the impulse response - Walter: The IBIS 5.1 flow is used for each channel, upstream and downstream - The only question is the waveform given to the redriver TX - Ambrish: The stimulus is different - 2) Combinations of Init_Returns_Impulse and GetWave_Exists - Walter: The primary TX gets digital stimulus - The redriver TX gets a different stimulus - Fangyi: The redriver TX is not event driven - Arpad: Does the BIRD describe this? - Fangyi: Yes - Arpad showed BIRD 156 - Bob: The terms "upstream" and "downstream" should be defined - Mike: Numbers should be used, there can be more than two - Radek: The BIRD introduction makes it clear - Arpad: That will not go into the spec - Bob: This needs to describe output and input impedances - Fangyi: That is described (Arpad highlighted) - Bob: That was not an assumption for all AMI models - Walter: Between each TX and RX is an analog channel - Between each RX and TX is an algorithmic channel - Every analog channel is analyzed the same way - The issue is how to analyze the RX to TX channels - If RX has no GetWave, how to generate waveform for TX? - Ambrish: IBIS 5.1 describes this - You convolve the stimulus with the impulse response - Fangyi: For this diagram it doesn't matter if GetWave is used - Arpad: If the left channel has no GetWave the output will have to be convolved to get the second TX input - This will have to be specified - Todd: The only valid statistical flow is when they all have Init - It's not hard to figure out, but it has to be specified - Arpad: This is bringing back Use_Init_Output - Todd: SiSoft never agreed with Use_Init_Output - Fangyi: We should not have to get into this now - Todd: What needs to be done is not said - Fangyi: It is in step 7 - Todd: I'm not sure that works, this is RX to TX - Fangyi: It is always RX to TX - Walter: We should not have to debate that it works, we just need to specify it - Ambrish: We have been doing it - Todd: We probably are all doing the same thing, but it is not specified - Walter suggested a sentence that would specify what is needed - Fangyi: That is what step 8 says - Todd: Most likely the RX is GetWave only and the TX is Init only - How is that handled? - Fangyi: Follow step 8 - Arpad: We still need to describe how the left channel connects to the right - Todd: What if the RX does not have GetWave? - Fangyi: It still has an output waveform - Todd: Step 8 says "output waveform of the redriver's input algorithmic model" - Arpad: Init has no waveform - Ambrish: It is the waveform maintained by the simulator, the channel waveform - Walter: No cases require deconvolution, we should be able to describe all cases - We only need to describe the redriver RX to TX path flow - Ambrish: We should refer to channels by number - Arpad: An Init only TX can only receive an impulse response, not a waveform - Walter: On page 2 a word "output" should be "input" - Fangyi: Agree - 3) Jitter and Noise - Walter: We should not prohibit noise modeling in redrivers - Fangyi: How can you add jitter to an analog waveform? - Todd: It will be handled elsewhere - Walter: It says GetWave handles noise, but Gaussian can't be handled there - Todd: We mostly suggest not precluding it here, from a standards viewpoint - Dropping the paragraph would do it - Fangyi: We will look at that AR: Fangyi update BIRD 156 per task group feedback ------------- Next meeting: 14 May 2013 12:00pm PT ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives