Minutes from August ibis-atm meetings are attached. Mike
IBIS Macromodel Task Group Meeting date: 07 Aug 2012 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 Arrow Electronics: Ian Dodd Cadence Design Systems: Terry Jernberg * Ambrish Varma Feras Al-Hawari 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 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 Sigrity: Brad Brim Kumar Keshavan Ken Willis 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: - Mike: Having trouble with eda.org email reflector - Please send email to ibis-macro@xxxxxxxxxxxxx, ibis -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Arpad prepare example BIRD 125 IBIS file set - not done - Bob to propose a simpler way for addressing the needs of parameter passing under [External Model] and [External Circuit] - not done ------------- New Discussion: Walter showed a presentation "IBIS-ISS Package Modeling": - slide 1 to 3 are overview slides - slide 4: - Walter: Aggressor channels may be less accurate than victim, but must model crosstalk well - slide 5: - Walter: Drivers are on the same chip for FEXT - slide 6: - Walter: Banks imply associations between groups of buffers - slide 7: - Walter: The syntax used here is mostly to highlight the required functionality - Some materials are from vendors who can not be named, some can - slide 8: - Walter: Voltage supplies can have one name but multiple nodes - May need to support resistors in package - There is some redistribution of power and ground pin to pin - [Pin Mapping] may have some overlap, need to investigate - Alternative is to add Pullup_Signal_Name and Pulldown_Signal_Name - Arpad: It may be wise to stay away from [Pin Mapping] for new package syntax - Walter: That may be a rat hole - slide 9: - Walter: Cdie and Rdie may not represent the interconnect complexity well enough - slide 10: - Walter: This shows how the syntax might work together - Slide 11: - Walter: Die names here could be called "implicit" - X and Y coordinates are added to support MCP - Not fully advocating this feature - Fangyi: What are the units? - Walter: It is given here as "inch", but it could be microns for silicon - slide 12: - Walter: Supply die data are given separately here - These are explicit die names - slide 14: - Walter: Both implicit and explicit die names are used here - On-die models are assigned by name - Ports are listed in the order they appear in ISS - slide 15: - Walter: The package model example here passes Length in as a parameter - slide 16: - Walter: Pin names here are the high pins of diff pairs - This should cover 99% of package usage - slide 17: - Walter: This should handle 90% of package model cases - slide 18: - Walter: VDD and VSS are used to denote associated supplies - slide 19: - Walter: Not sure if this section about resistors is correct yet - slide 20: - Walter: This has 2 DQ aggressors and 1 DQS aggressor - The model name for the NEXT aggressor is given - DDR3 models tend to give values from standards, not what the part does - Fangyi: Is this saying where crosstalk is coming from? - Walter: The industry requires the aggressor and victim models to be the same - slide 21: - Walter: Some vendors want to supply more than 3 corners - This uses the {squiggly bracket} substitution syntax - slide 22: - Walter: It would be convenient to just use a Touchstone file, if that is all that is needed - slide 23: - Walter: Some models will describe a whole interface - Some terminals may not be correct in this example - slide 23: - Walter: Some models will describe a whole package - NC is used to leave some ports unconnected - Reduced s-param models can be derived from larger ones - slide 24: - Walter: They should be organized by sij instead of frequency to make it easier - slide 25: - Walter: A Perl script can produce the derived parameter syntax - slide 27: - Walter: Everything for package models can be used for on-die models - slide 28: - Walter: There are a few errors in this example - Slides 29 & 30: - Walter: These show an example for banks - Any number of voltage supplies can be passed in - slide 31: - Walter: I have tried to cover everything that others have requested - Is anything else required? - Do we need all that is here? - James: All signals are point to point, that should be a category - People want to see coordinates because we get power models with just one node name for all - Need to regroup into different quadrants - Walter: A connection could have just one supply name and several bumps - James: Are the victim features a superset of the aggressor features? - Walter: Correct - Arpad: Are the different examples using the same syntax? - Walter: An interface model is different - Only the victim channel is valid - Only that one has all the crosstalk modeled - Aggressors only generate noise - The syntax for them is different - The port order has "Pin" and "Pad" notation, for example - For interface models have actual pin and bump numbers - In interface models everyone is both victim and aggressor - Fangyi: In victim models you need to say which channel is valid - Walter: The ones with reserved names are the victims - Fangyi: We should be able to quickly identify which models are aggressor - Walter: That is a constraint of the person generating the subckt - Fangyi: Why specify aggressors? - Walter: They appear at a certain point in the subckt port order - There may be better ways to give this information - Arpad: This should be done in a more general way - Fangyi: You may want to analyze only 1 of 100 channels, and only a few neighbors matter - Walter: We need to know the pin and pad of each victim and aggressor - James: Pad is on the die side? - Walter: Pin is pin name and pad is bump pad - We need a consistent naming convention - Arpad: Using the P side of diff pairs only works if names are sequential - Walter: The [Diff Pin] section gives the other side ------------- Next meeting: 14 Aug 2012 12:00pm PT Next agenda: 1) Task list item discussions ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives
IBIS Macromodel Task Group Meeting date: 14 Aug 2012 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 Arrow Electronics: Ian Dodd Cadence Design Systems: Terry Jernberg * Ambrish Varma Feras Al-Hawari 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 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 Sigrity: Brad Brim Kumar Keshavan Ken Willis 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: - None -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Arpad prepare example BIRD 125 IBIS file set - not done - Bob to propose a simpler way for addressing the needs of parameter passing under [External Model] and [External Circuit] - not done ------------- New Discussion: Walter showed a presentation "IBIS-ISS Package Modeling Discussion": - This is already on the web site - slide 2: - Walter: Would like to have open discussion, hoping to answer questions today - slide 3: - Walter: Do we need supply voltages? - Do we need XY coordinates? - The NEXT/FEXT discussion was confusing, there is a better way to describe this - slide 4: - Walter: What voltage should be applied to the package pin? - Bob: IBIS already addresses this - It is specified at the model - Randy: [Pin Mapping] specifies this - Walter: Two models could be connected to VDD with different voltages - slide 5 & 6: - Walter: XY is more reliable than CAD net name or pin number - Coordinates help generate package and die models, but are not needed in them - Arpad: IC vendors should know what the die and package look like by the time they have IBIS - slide 7: - Walter: Someone said [Pin Mapping] should not be used - This proposal is to give power and ground signal names in the models - Arpad: BIRD 145 is similar - slide 8 & 9: - Walter: A hierarchical numbered port description scheme is better than positional port names - This distinguishes between pins and pads - slide 10: - Walter: Here is an example using model names and polarity - I will post corrections to this slide - slide 12: - Walter: Multi-channel coupling can be described with Channel and Victim parameters - Supply names like VDD are given here too - Radek: Does this give the model name like the [Component]? - Walter: No this is a package model - slide 13: - Walter: This format can be use to specify sparse ports to extract from an s1000p - Walter: We can have questions here - James: How do we map pin to die pad? - Power pins map many to many - Walter showed a [Pin Die Data] example from his previous presentation - Walter: This shows how implicit die pad names allow for that mapping - James: Does this work for power? - Walter: Many old IBIS files have NA for all power pins - The [Supply Die Data] slide shows many to many mapping - Walter showed the Rambus example to explain further - Ambrish: Could smaller channels make more use of the crosstalk info? - Walter: Package models are made by interface, quadrant, bank, whole package etc. - No one simulates the whole package - Ambrish: In IBIS we mostly care about channels - Walter: We must decide what needs this satisfies and which to support - Randy: Is there a way to handle multi-die? - This is badly needed - Walter: That is the next step, we can modify EBD - I proposed EMD a few years ago, it should be easy to add the new features to EBD - Greg: The intention is to support existing and new models? - Walter: Existing IBIS does not have IBIS-ISS - Greg: It seems this is about helping to extract from boards - Walter: This is not about that - Walter: There may be too much functionality listed here - Next we must decide how to proceed - BIRDs 125 and 145 may or may not have all that is needed - My approach is model based, not pin based - A model can give data that applies to many pins - In BIRD 125 the on-die model calls the buffer models - Here the die is just between the existing models - James: More details would be needed to compare this to Arpad's proposal - Walter: Yes, much work is needed once we choose a path - James: It needs to be organized so models from different companies/divisions can work - Walter: The interfaces are all by pin/model/die names - Arpad: Do we need to decide syntax or functionality - Walter: Functionality - The syntax could be keyword or parameter trees - Parameter trees can be very powerful - Arpad: BIRD 125 could be extended to cover all of this - So syntax is the only difference - The questions are about large s-params, XY coordinates, voltages - Walter: I have been unable to see how to extend BIRD 125 - Arpad: The question is if we need all this functionality - Walter: We could vote feature by feature next week - Arpad: One general purpose syntax might satisfy all of them - Questions could be whether we want RC circuits, LC circuits, etc. - We do not need to choose because IBIS-ISS can do all of them - Ambrish: It would be good to have the voting list emailed in advance AR: Walter email a list of package modeling features for voting ------------- Next meeting: 21 Aug 2012 12:00pm PT Next agenda: 1) Task list item discussions ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives
IBIS Macromodel Task Group Meeting date: 21 Aug 2012 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 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 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 Sigrity: * Brad Brim Kumar Keshavan Ken Willis 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: - Bob: Would like to address IBIS parser issues -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Walter email a list of package modeling features for voting - Done - Arpad prepare example BIRD 125 IBIS file set - not done - Bob to propose a simpler way for addressing the needs of parameter passing under [External Model] and [External Circuit] - not done ------------- New Discussion: Bob discussed AMI changes in the new IBIS parser: - Bob: Initially there was a warning for parameter name collisions - It now checks for collisions only within each branch - The leaf check for Description has been fixed, allowing only one per branch - Arpad: This Friday might be the big day for IBIS 5.1 Luis Armenta introduced himself: - He is working on AMI models at ANSYS Walter showed a presentation: - Walter: This presentation has been sent out - It summarizes use of parameter trees and IBIS-ISS for various models - Some slides are brief summaries - slide 5: - Walter: This example explains the proposal for packages - slide 6: - Walter: This tree shows a typical on-die model - There are 4 bump pads for power and ground - Power and signals could be merged together - slide 7: - Walter: This package model tree looks similar to the on-die one - slide 8: - Walter: This adds length modeling where that is known - slide 9: - Walter: This package tree shows victims and aggressors for crosstalk - slide 10: - Walter: Arpad asked for both package and on-die trees here - This makes the model understandable and easy for EDA tools to use - slide 11: - Walter: [Path Description] can be converted programmatically to IBIS-ISS - slide 12: - Walter: Here is a legacy EBD file - It has comments to show what things are - Arpad: Do the slashes precede comments? - Mike: They are for continuation, pipe characters for comments - Walter: I may have modified this - slide 13: - Arpad: The red line doesn't say how the IBIS-ISS package is connected - Walter: Good point but we will not be pursuing that - slide 15: - Walter: Gd and RS are critical, but EBD doesn't support them - slide 16: - Walter: This replaces a path description - James: Is U1 a reference designator? - Walter: Yes, this EBD is for a DIMM board - Fangyi: Would this work without the pin order? - Walter: That could work - slide 17: - Walter: EMD "module" is less constraining than EBD "board" - slide 18: - Walter: This is the legacy EBD converted to EMD - The only new thing here is Diff_Pins - slide 19: - Walter: Nothing is different for a connector - Defining the A and B sides may not be necessary - Vendors often give slice models from which all pins are derived - Fangyi: The unconnected pins are assumed to be open? - Walter: Or 50 ohms to ground, etc. - A typical method is to extract a smaller s4p - Fangyi: It still depends on what is assumed for the other ports - Walter: They are effectively open - Radek: That will not work - Arpad: Some models are not symmetric in each direction - Walter: The A and B signal names handle that - slide 20: - Walter: Some of our existing BIRDs are gobbledygook - There is confusing baggage - slide 21: - Walter: [External IBIS-ISS Model] is a simple way to handle it - Stimulus and other items are easily defined in tree format - Arpad: Stimulus is what the DtoA converters handle - This is a new keyword for something that exists - Walter: The Model_Ports syntax is very simple - slide 22: - Walter: We should reject the listed BIRDs and create a new IBIS 6.0 EMD section - I will make this motion Friday at the Open Forum meeting - slide 21: - Fangyi clarified how the TX Stimulus parameter works with the model ports - Walter: IBIS-ISS is invalid for most buffer models because it can't handle input and enable - PWLs or macros would have to be added, as in IBIS-BSS - Model_Ports is similar to Model Connection Protocol - James: How to tell which ports are connected to stimulus? - Walter: Drive is a reserved name for that - We might want to call that Stimulus - This attempts to not make too many changes - It will be a lot of work to write this BIRD, it should be a group effort - Fangyi: Coloring the reserved names may help avoid future questions - James asked about the format of the Tstonefile parameter - Walter: It goes into the AMI file to get the value - Some AMI models have many "knobs", and some change the Tstonefile - Radek: The right side model is used only with AMI models? - Walter: Values can be directly specified here - slide 22: - Ambrish: This replaces all of the BIRDs proposed for rejection? - Walter: Yes, for example the package and on-die models replace [Circuit Call] - What I'm proposing requires only one new parser AR: Walter send slides with modifications for posting Bob: This Friday IBIS 5.1 is the priority - There may not be much time for other items ------------- Next meeting: 28 Aug 2012 12:00pm PT Next agenda: 1) Task list item discussions ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives
IBIS Macromodel Task Group Meeting date: 28 Aug 2012 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 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 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 Sigrity: * Brad Brim Kumar Keshavan Ken Willis 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: - Arpad: Should we meet next week, given the labor day holiday? - No one said they can not attend - We will meet next week? - Arpad: Should we allow TX and RX of different AMI_Version in the same simulation? - Walter: This is somewhat academic - Only one old model has Use_Init_Output - Our tools will have no problem - Mike: Models from different vendors might be in the same simulation - Arpad: The question is whether to allow it in the specification - Radek: The spec already allows an older model to be in a newer IBIS file - Arpad: The question is if they should be allowed in the same simulation - Radek: We can't restrict that, people will mix models - Walter: Certain combinations require deconvolution - The math for that is clear, this is not a problem - It is a rare case anyway - Radek: We could post guidelines outside of the IBIS spec - Michael M: Thank you to the group for making IBIS 5.1 a reality - Greg: We should discuss roadmap, especially packaging - Arpad: There is an agenda item for that -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Walter send slides with modifications for posting - Done - Arpad prepare example BIRD 125 IBIS file set - Not done - Will do this only if we keep BIRD 125 - Bob to propose a simpler way for addressing the needs of parameter passing under [External Model] and [External Circuit] - Not done - We can drop this ------------- New Discussion: Arpad: We need to discuss what is next for our group - Walter showed a presentation "IBISx" - slide 2: - Walter: Legacy IBIS has everything in one file - Package information should be in a separate EMD file - slides 3 & 4: - Walter: Translating an legacy package model to EMD is straightforward - slide 6: - Walter: The die model is similar - slide 7: - Walter: Models also translate easily - slide 9: - Walter: This is the roadmap - Some BIRDs should be rejected - Some BIRDs that are AMI related would not be rejected, go into 5.2 - Backchannel BIRDs would be in 5.3 - We have not seen demand for backchannel modeling - New BIRDs for 6.0 will be needed - Ambrish: We should make backchannel higher priority - Walter: That is OK - Gennum has asked for it, but not many users yet - Arpad: We should have a new category for analog models - Radek: This is an overhaul of the general IBIS syntax - Legacy IBIS has no clear hierarchy - We need to analyze what we gain and lose - Greg: Do we maintain backward compatibility? - Walter: No, this is a new standard - Bob: I am not in favor of splitting IBIS into different sections - IBIS will continue for a while - Walter: It will continue but we do not have to maintain it - I/V curves and other things would be reused, not reinvented - Arpad: We explored going to equation based models - This might be a good time to revisit that - Walter: Yes, that might be an additional parameter to Legacy and IBIS-BSS - Kumar proposed parameter trees years ago, and they are easy to work with - James: This is mostly about syntax - Are we propose any changes to the functional part? - Walter: Adding a Tstonefile is a functional improvement, for example - Ambrish: The other proposal is to use IBIS-ISS - Arpad: This is starting over - It might take years to finish this - Can a well defined analog model wait that long? - Walter: I think this can be done in six months - Arpad: IBIS 5.1 took 4 years - John: AMI was going to be simple too at the beginning - I don't see a difference - Arpad: It could take quite a while to do equation based models - Walter: Yes, but I am proposing stuff we already know how to do - Originally we made mistakes because we did not understand the problems - We have better understanding now of the physics - Arpad: Writing a specification is not just about physics - Getting vendors to agree on details can be difficult - James: We need to address the question of what problem we are trying to solve - Walter: IC vendors need to supply broadband package and on-die models - For both signals and power delivery - Arpad: The point is that we don't have to rewrite the syntax for that - James: We need to analyze how this helps achieve that - Walter: We still have no example of how to create needed models with the existing BIRDs - On-die models are independent of package models - John: Having just a proposed syntax may not help enough - Michael M: We should have a drawn example, not in the proposed syntax - Then see what it takes to create examples - Walter: Greg said he was willing to supply examples - Arpad: We could try that - Walter: IC vendors should report what they can supply and what they want AR: Greg and Michael M provide examples to show what IC vendors need Bob: I do not agree with the roadmap slide - We should not assume that it has been accepted ------------- Next meeting: 04 Sep 2012 12:00pm PT Next agenda: 1) Task list item discussions ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives