Subject: [IBIS] IBIS v4.0 additions and BIRD75
From: Muranyi, Arpad (arpad.muranyi@intel.com)
Date: Fri May 31 2002 - 14:59:41 PDT
To All,
As I mentioned in today's IBIS Open Forum meeting, I wanted to find out
how much of the IBIS v4.0 features would be obsolete if BIRD75 was
implemented. The reason being that if tool vendors can free up some
resources by not having to implement so many new features from the v4.0
additions, they could put more energy into implementing the much needed
BIRD75 features more quickly.
In order to find the answer to the above question, I compiled a list with
all of the BIRD titles, keywords and subparameters that are proposed for
the IBIS v4.0 specification. I included the keywords and subparameters
which are effected as a reminder. (Note that not all these keywords and
subparameters are additions to the spec, and not all of them are necessarily
effected either, they are just shown as a reminder). Stephen an I got
together today and wrote comments below each of these BIRD items to see
how useful they were, and how difficult their implementation may be.
Surprisingly, the outcome of our evaluation is that there are only a very
few BIRDs which could be omitted.
Please look over the list and comment.
Thanks,
Arpad
==========================================================================
BIRD62.6 Enhanced Specification of Receiver Thresholds
[Receiver Thresholds]
Vth, Vth_min, Vth_max, Vinh_ac, Vinh_dc, Vinl_ac, Vinl_dc,
Threshold_sensitivity, Reference_supply, Vcross_low,
Vcross_high, Vdiff_ac, Vdiff_dc, Tslew_ac, Tdiffslew_ac
- doesn't effect model behavior
- used for automated report generation of buffer specification violations
- may be relatively easy to implement in tools(?)
- JEDEC specifically asked for it (DDR)
- may be superceded by full receiver modeling in AMS languages (BIRD75)
- KEEP IT
BIRD64.4 Alternate Package Models
[Alternate Package Models] [End Alternate Package Models]
- doesn't effect model behavior
- used for automatically switching package models (GUI feature)
- may be relatively easy to implement in tools
- BIRD75 doesn't address this
- may be superceded by the more accurate package models of the new
IBIS interconnect specification, eliminating the need for multiple
SLM models to describe even, odd, etc. modes
- KEEP IT
BIRD65.2 C_comp Refinements
[Model]
Model_type, Polarity, Enable, Vinl, Vinh, C_comp,
C_comp_pullup, C_comp_pulldown, C_comp_power, and
C_comp_gnd Vmeas, Cref, Rref, Vref
- does effect model behavior
- frequency domain analysis requires more extensions to C_comp
(see Luca's presentations on this subject)
- may be relatively easy to implement in tools
- AMS language models can do a better job (BIRD75)
- HSPICE B-element has it implemented already
- useful especially if BIRD75 implementation is slow in tools
- KEEP IT(?)
BIRD66 [Model Spec] Vref Addition
[Model Spec]
Vinh, Vinl, Vinh+, Vinh-, Vinl+, Vinl-, S_overshoot_high,
S_overshoot_low, D_overshoot_high, D_overshoot_low,
D_overshoot_time, Pulse_high, Pulse_low, Pulse_time, Vmeas
Vref
- doesn't effect model behavior
- used for automated flight time measurements
- only one additional subparameter to implement
- may be relatively easy to implement in tools
- BIRD75 doesn't address this
- KEEP IT
BIRD67.1 Increase V-T Table 100 Point Limit
[Rising Waveform], [Falling Waveform]
- makes existing models more accurate without algorithm changes
- this is just an IBIS specification change
- may be relatively easy to implement in tools
- AMS language models can be still more accurate (BIRD75), but not
really relevant to BIRD75
- KEEP IT
BIRD68.1 Clarify that Rising and Falling Waveforms Should be
Correlated
[Rising Waveform], [Falling Waveform]
Just text in the spec.
- this is just an IBIS specification clarification change
- not relevant to BIRD75
- KEEP IT
BIRD70.5 Golden Waveforms
[Test Data]
Test_data_type, Driver_model, Driver_model_inv, Test_load
- doesn't effect model behavior
- used for (automatic) validation of IBIS models through simulations
- this is more of a user interface feature
- may be relatively easy to implement in tools
- BIRD75 doesn't address this
- KEEP IT
BIRD71 Timing Test Loads in [Model Spec] to Support PCI & PCI-X
[Model Spec]
Vinh, Vinl, Vinh+, Vinh-, Vinl+, Vinl-, S_overshoot_high,
S_overshoot_low, D_overshoot_high, D_overshoot_low,
D_overshoot_time, Pulse_high, Pulse_low, Pulse_time, Vmeas
Vref, Cref, Rref, Cref_rising, Cref_falling, Rref_rising,
Rref_falling, Vref_rising, Vref_falling, Vmeas_rising,
Vmeas_falling.
- doesn't effect model behavior
- tool automation feature for timing measurements
- this is more of a user interface feature
- may be somewhat difficult to implement in tools (complicated)
- BIRD75 doesn't address this
- KEEP IT
BIRD72.3 Accommodating PMOS and NMOS//PMOS Series FET Models
[Series MOSFET]
The definition of Voltage in the IV table changes.
- doesn't effect model behavior(?)
- interpretation change of IBIS model data to expand usage
- may require some algorithm changes in tools
- AMS language models can do a much better job (BIRD75)
- KEEP IT
BIRD73.4 Fall Back Submodel
[Submodel]
Dynamic_clamp, Bus_hold, Fall_back
- does effect model behavior
- used for AVC technology drivers
- not applicable for de-emphasis/pre-emphasis buffers
- may be relatively difficult to implement in tools
- AMS language models can do a much better job (BIRD75)
- complexity vs. need issue... is it needed soon, or can
we wait for BIRD75 to be implemented in tools?
- CANDITATE FOR REMOVAL, DEPENDING ON COMPLEXITY VS. IMMEDIATE NEED
P-----BIRD74 EMI Parameters
[Component EMI]
Component_type, Domain, Family, Family_spec
- pending BIRD
- doesn't effect model behavior
- not addressed by BIRD75
P---BIRD75.1 Multi-Lingual Model Support
[External Model], [End External Model]
- Extended model description
[External Circuit], [End External Circuit]
- Circuitry on the die
[Node Declarations], [End Node Declarations]
- Interconnect nodes
[Circuit Call], [End Circuit Call]
- Connection description
==========================================================================
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