[ibis-macro] Minutes from the 14 Feb 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 28 Feb 2012 09:41:55 -0500
Minutes from the 14 Feb 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 14 Feb 2011
Members (asterisk for those attending):
Agilent: Fangyi Rao
* Radek Biernacki
Altera: * David Banas
Ansys: Samuel Mertens
* Dan Dvorscak
Curtis Clark
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
Feras Al-Hawari
Celsionix: Kellee Crisafulli
Cisco Systems: Ashwin Vasudevan
Syed Huq
Ericsson: Anders Ekholm
IBM: * Greg Edlund
Intel: Michael Mirmak
LSI Logic: Wenyi Jin
Maxim Integrated Products: Mahbubul Bari
Mentor Graphics: * John Angulo
Zhen Mu
* Arpad Muranyi
Vladimir Dmitriev-Zdorov
Micron Technology: Randy Wolff
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
The meeting was lead by Arpad Muranyi
------------------------------------------------------------------------
Opens:
- Arpad: I can not meet next week
- Walter moved to cancel the next meeting
- Bob seconded
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Arpad propose method to generalize BIRD 118
- In progress
- Cadence update BIRD 144
- Done
- Mike post Walter's updated presentation to ATM website
- Not done
-------------
New Discussion:
Naming Rules BIRD (new):
- Walter: Some characters that are allowed in parameter names are inconvenient
for some parsers
- The tap parameter violates our rules because names begin with numbers and
'-'
- We should be able to observe the new rule for future Reserved Parameters
- For example, Dual-Dirac becomes Dual_Dirac
- Should this go into 5.1 or 5.2?
- Arpad: This is inconvenient for script languages but not urgent
- Walter: Adge Hawes wants this change
- Arpad: How are script languages affected by dashes?
- It is just a string to be parsed
- Walter: The parameter names can not easily become identical names in the
other languages
- Variable in many languages can't start with a number or have special
characters
- Ambrish: Should we just voluntarily avoid those names?
- Walter: We can't voluntarily avoid the rules for Type Tap, because they are
in the spec
- Tools might use aliases to support those requirements
- Bob: I'm neutral on this
- Ambrish: Are number names really required for taps?
- Walter read aloud the description of Type Tap
- Radek: That is just an example, not a requirement
- Arpad: If this is correct then we may have a tap ordering problem
- We should look at this more carefully
- Ambrish: It is an error to use tap values other than numbers
- Radek: Agree with Arpad, we should look at this
- James: What does "alias" mean here?
- Walter: FOr example Dual_Dirac would be an alias for Dual-Dirac
- James: Why not remove Dual-Dirac?
- Walter: I would not object, but we would lose compatibility
- Our general philosophy is to maintain backward compatibility
- Arpad: There is a deadline to be considered for 5.1
- James: The spec says the model developer decides whether to follow convention
- Walter: A, B, C could be used
- That might be valid for floating taps
- Ambrish: The model will understand it regardless
- Arpad: How does the EDA tool understand them?
- Ambrish: It doesn't have to
- James: These are Model_Specific parameters
- We should pick one name, but not both
- Walter: If numbers are used the tool can see which are pre and post cursor
taps
- The tool can look at In parameters and use them
- Radek: The names could be more informative, like Pre, Main, etc.
- Arpad: We will have issues if tools can use In params themselves
- Walter: The tool might manipulate the values specially, for backchannel for
example
- Ambrish: The model might expect a set of tap numbers without parameter names
- James: It will be a user issue if the tool is changing taps
- It has to work the same way across tools
- Radek: ???
- Arpad: The names have to be meaningful if the tool is to use them
- We would need a tap naming convention
BIRD 118:
- Arpad: BIRD 118 has names changed to a more generic format
- The same changes will be needed in BIRD 117
BIRD 144:
- Feras: We removed references to user defined corners
- We added a port termination subparameter
- It can be use with [External Model]
- Need to tell EDA tool how to terminate floating power
- Termination is given as resistance and voltage
- Walter: Unterminated implies it is not hooked up
- It would be simpler with an ISS subckt
- Sometimes a 50 ohm ground is needed, sometimes it must be absent
- We should find out about the derivation methods for S4Ps
- Arpad: This relates to the isolation amplifier topic
- We need to address ports that are not connected
- Feras: With [External Model] we have to give information on unconnected ports
- Walter: The port set is defined there
- How can there be "additional" ports?
- Feras: A model might have only in and out ports
- How will the tool hook up power?
- Radek: With ISS those connections are available
- The circuit seems to assume ground
- It provide a means to specify that may not be needed
- Feras: Different buffer types may have different numbers of terminals
- There are assumptions in the tools about 7 terminals, for example
- Walter: [External Model] does not make that assumption
- Arpad: Node declarations can help but they are not required
- Feras: I can update to add that if we agree
- Arpad showed the [External Circuit] diagram in IBIS 5.0
- James: It would help to map the proposal to the diagram
- Arpad: The node names do not mean much here
- Can't recall if [External Model] covers handling of extra nodes
- Walter: What problem are we solving?
- Feras: An [External Model] can have a transistor buffer model
- [External Circuit] can have complex parasitics
- James: Why fit into 7 ports if Touchstone can have many more?
- Feras: It would be best to directly call Touchstone
- James: That is just another way wrapping, which we can already do
- Feras: It will be easier for my version of SPICE to deal with it
- James: An example would help
- Walter: These are shortcuts, but not clearly defined
- Feras: It is easier to use with classic IBIS models
- Arpad showed a wrapper example called "A"
- Feras: We should not have to write wrappers for this every time
- Arpad: BIRD 144 adds direct Touchstone instantiation, mine doesn't
- Feras: Walter said 145 allows cascading, 144 doesn't
- Arpad: For boundary conditions the Touchstone model better have zero drive
impedance
- Feras: There is a problem with floating nodes
- Walter: We have floating nodes all the time
- We just connect with a resistor to ground
Meeting ended.
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Next meeting: 28 Feb 2011 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
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