Subject: Re: [D]SPF for back-annotation?
From: Pragmatic C Software (sjmeyer@pragmatic-c.com)
Date: Sun Feb 04 2001 - 20:51:04 PST
Correct me if I am wrong, but my impression is that analog models such
as bsim 2 annotation is mostly through parameters. SDF can annotate to
any AMS HDL object such as parameters, bodies (gates, instances, transistors),
declarations, analog contribute statements, branches, etc. I do not
understand how say cross talk is represented in Verilog-AMS. SDF is intended
for post delay calculator values except non actual delay parameters can be
annotated too - usually because the Verilog model does computation say computes
loading formulas before using final value as a procedcural (usually) delay.
Digital models are more and more moving to some delay calculation performed
by HDL from annoatated to values.
Currently, when new constructs are added to Verilog HDL, new SDF forms
are added to SDF.
/Steve
Quoting Kevin Cameron x3251 (Kevin.Cameron@nsc.com):
> > From pragc@www.tdl.com Fri Feb 2 18:01:36 2001
> >
> > Why not use SDF? It is already supported by every Verilog simulator and the
> > infr-structure of programs for handling name conflicts, etc exists.
> > It is extensible. There also are some new features for Verilog 2000
> > that allow annotating to procedural behavioral code so extensions to allow
> > annotating to analog blocks and spice should not be too hard.
> > /Steve
>
> We need to be able to back-annotate analog circuitry, SDF is only good for
> digital timing - e.g. it doesn't cover crosstalk, mutual inductance or
> transmission line effects.
>
> The easiest way to handle the stuff (IMO) is to allow the inclusion of
> extra circuitry in the HDL description (e.g. the full SPF) and then reconnect
> the ports of the un-annotated design into it - but you need a way of disabling
> the bits of the SPF that are covered by the un-annotated design (which is
> awkward if it is flat).
>
> We also need to be able to mix SDF & SPF in a single design.
>
> Kev.
-- Steve Meyer sjmeyer@pragmatic-c.com
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