[Qucs-devel] Mixed-signal support (and other stuff)

[Kevin C. <cam...@gm...>]

Just to introduce myself -

I have worked on a couple of VHDL simulators, Verilog (VCS), Verilog-AMS
(HSpice), and participated in the language development of Verilog-AMS since
the start, and some of SystemVerilog.

I designed the mixed-signal "connect module" methodology for Verilog-AMS
that allows automatic connection of analog and digital parts of simulation.

History:

My original design for the AMS stuff got broken by Cadence during the
standardization and has never worked properly in commercial tools (except
maybe Antrim's which Cadence bought and shelved).

Cadence blocked moving Verilog-AMS into SystemVerilog and off to the IEEE,
and the IEEE effort has been constrained to IEEE-SA members only
($5k+/year) - most of whom are not interested in mixed-signal (or anything
that smells of analog).

So the only IEEE HDL that supports both analog and digital is VHDL, but it
has a bunch of semantic problems that make it difficult to use.

Plan:

Since the official language development committees don't seem to be able to
address mixed-signal issues sensibly I'd like to fix this in the open
source community, and VHDL seems like it might be a better option at the
moment since it has no conflicting methodology.

The goal of the exercise is to support better modeling for SoC with power
management (variable voltage supplies) and wiring issues, so it's not
particularly about precision analog, and I would like to support discrete
modeling of analog (for parasitic Rs &Cs). However, a precision analog
kernel may become available in open-source soon and I may look at how to
integrate that.

Longer term I would like to develop a C++ API layer so I can bolt together
the VHDL and Verilog stuff independent of the higher level language specs,
and I have a project to support that on a back burner (http://parallel.cc).


So if anybody would like to help make VHDL be the language it should have
been, I'll post what I think needs to be done at the language level and
internally to the simulator(s).

Kev.