IBIS Macromodel Task Group Meeting date: 07 April 2015 Members (asterisk for those attending): Altera: * David Banas ANSYS: * Dan Dvorscak * Curtis Clark Avago (LSI) Xingdong Dai Cadence Design Systems: * Ambrish Varma Brad Brim Kumar Keshavan Ken Willis eASIC David Banas Ericsson: Anders Ekholm IBM Steve Parker Intel: Michael Mirmak Keysight Technologies: * Fangyi Rao * Radek Biernacki * Nicholas Tzou Maxim Integrated Products: Hassan Rafat Mentor Graphics: * John Angulo * Arpad Muranyi Micron Technology: * Randy Wolff Justin Butterfield QLogic Corp. James Zhou Andy Joy eASIC Marc Kowalski SiSoft: * Walter Katz Todd Westerhoff * Mike LaBonte Synopsys Rita Horner Teraspeed Consulting Group: Scott McMorrow Teraspeed Labs: * Bob Ross (Note: Agilent has changed to Keysight) The meeting was led by Arpad Muranyi. ------------------------------------------------------------------------ Opens: - None -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Michael M update AMI Directionality BIRD - No update - Walter and Randy produce C_comp BIRD. - Arpad: Some work has been done and this has been posted. - Arpad to review IBIS specification for min max issues. - In progress. ------------- New Discussion: Pin merging: - Arpad: I had proposed some changes. - Arpad showed an example for a proposed change. - Arpad: Bob had proposed a new keyword instead of a subparameter. - This shows [Merged Pins], prepared by Randy. - Randy: Line wrapping needs to be allowed. - Arpad: In the second format the main pin follows the keyword. - Other connected pins are on the next line. - Radek: How does this relate to IBIS line continuation rules? - Bob: I prefer the two line format. - You can comment them that way. - Walter: These are not consistent with the pin list above. - For example K9 is absent. - Arpad: That is because there is no model for K9. - Radek: But it must be on the component. - Walter: These issues will go away with the new package model. - Bob: This doesn't force using signal names for merged pins. - Arpad: We found that [Pin Mapping] did not work the same way in each tool. - But this BIRD addresses just the ambiguity for pins that are not in [Pin Numbers]. - The new package model capability will fully address it. - John: This can create a set of shorted pins that is not the same set as [Pin Mapping]. - Arpad: It's the same capability. - Bob: This can be used only with [Pin Mapping] present. - John: You can have two buffers on the die side using the same group of shorted pins. - Arpad: That is ruled out. - Bob: We want to avoid shorting power and ground. - Arpad: Near the die features become smaller. - It makes more sense to combine those. PAM4 BIRD: - Walter: The BIRD draft is up to revision 14 now. - I will send it with any changes to Mike for posting. - We should be able to forward it to the Open Forum with a recommendation. - It will not be ready for this Friday however. - Arpad: We should review the changes. - Walter showed the draft PAM4 BIRD. - Walter: The Modulation parameter can be Info if there is only one value. - It has to be In to have multiple values. - Bob: The Default must be . - Radek: Why does the Default have to be here at all? - Bob: That's how our rules work. - Walter: For List format Default makes sense, but not for Value. - Walter: PAM4_Mapping maps levels to symbols. - Grey code "0132" is the default. - Bob: Again the Default is a . - Even though it is Value only. - Walter: We have three thresholds for PAM4. - Arpad: We do not assume center for the middle threshold? - Walter: That is up to the model maker. - We allow InOut in case the model chooses it. - If not specified the EDA tool must determine thresholds. - Arpad: Is it specified how to do that? - Walter: It is up to the tool. - The thresholds really should be given. - There is also a PAM4_Receiver_Sensitivity, only for the middle threshold. - Bob: The Default should be . - We should support Dep usage. - Radek: Dep should be allowed for anything that can be Out. - Walter: We have timing offsets for the upper and lower eyes. - Bob: The Default must be described in the text. - Arpad: Scott McMorrow was asking about non-linearity. - Fangyi had said AMI_GetWave could handle it. - That should be explained. - Walter: It depends on what causes the non-linearity. - It will not happen in the RX analog section. - Voltage levels there are small, it will be linear. - In the TX there could be a voltage lookup table based on previous symbols. - It does not have to be a classic FFE. - Any non-linearity there probably is not about saturation. - Arpad: Fangyi said it might be a saturation effect. - Walter: Maybe only the impedance changes, but that's not voltage. - Arpad: This assumes the impulse response is done with an NRZ level. - Walter: It can be thought of as pulse or step too. - Fangyi: Should we allow Out for PAM4_Mapping? - Walter added a note for that. - We need to ask IC vendors about this. - Fangyi: We need to discuss the bit_time argument in AMI_Init - Walter: In PAM4 we have a symbol, not a bit. - For PAM4 it will be symbol time. - Mike: We could rename it to symbol_time - Arpad: We could say bit_time is scaled by symbols/bit. - Ambrish: Other places in the IBIS specification might need to change for this. AR: Walter send updated PAM4 BIRD to Mike for posting. C_comp: - Randy showed C_Comp Model BIRD draft revision 6. - Randy: ISS has been changed to IBIS-ISS. - An example has been reformatted to insert a format column. - A figure has been updated. - Radek: There is no A_gnd in there, we will need that. - David: Is the numbering of names required? - Randy: That is done to avoid conflicts. - The unnumbered nodes are at predefined locations. - Bob: Corner has to be described as a model corner. AR: Randy send updated C_comp BIRD to Mike for posting. ------------- Next meeting: 14 Apr 2015 12:00pm PT ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives