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Re: [Gnucap-devel] commands in verilog mode.
From: |
Nathan Kohagen |
Subject: |
Re: [Gnucap-devel] commands in verilog mode. |
Date: |
Fri, 30 Nov 2007 20:31:51 -0800 |
User-agent: |
Thunderbird 2.0.0.9 (X11/20071115) |
al davis said the following on 11/30/2007 04:13 PM:
Verilog doesn't specify commands. As far as I know, there are
no existing native Verilog-AMS simulators. It looks like
gnucap is leading here.
From what I see,in commercial simulators, Verilog-AMS is only
supported through something like a plugin mechanism. The main
circuit seems to be spice format, or maybe a proprietary
format.
...
comments?
Hi Al,
Related to adding support of Verilog-AMS, I think something that would
be great is support for a digital simulator (such as Icarus Verilog) to
control the gnucap analog kernel. When performing mixed-signal
simulations there is usually large amounts of digital with one analog
portion that you are targeting for the test and other analog blocks to
support the test.
What I am invisioning is a replacement for Mentor Graphics ADvanceMS
(Modelsim + Eldo) or Synopsys Discovery (VCS + Nanosim).
Support for Verilog-AMS could be accomplished as a preprocessor script
to split into the digital (Icarus Verilog = Verilog-D) and analog
(gnucap = Verilog-A/SPICE) kernels and link the whole mess together.
Verilog-AMS is really a superset, so I think we should be take pieces
that already good by themselves (Icarus and gnucap) and make them work
together.
Just getting a Verilog-D inverter in Icarus Verilog driving a SPICE
inverter in gnucap would be a good start.
Support for linking in SystemC and VHDL to digital simulations in Icarus
Verilog (would probably need a name change then) would nice. VHDL-AMS
could be handled as part of the preprocessor step like Verilog-AMS.
Adding Spectre support (as you have mentioned in recent postings) will
make the analog part of the equation even more flexible!
An interesting paper is on creating a mixed signal environment with
SystemC is:
"SEAMS - A SYSTEMC ENVIRONMENT WITH ANALOG AND MIXED-SIGNAL EXTENSIONS"
by H Aljunaid and T J Kazmierski in ISCAS 2004.
It describe the lock-step execution that needs to take place between the
digital and analog kernels - rewinding the time-step, etc.
If gnucap was made to work with Icarus Verilog it would be also be
controllable from SystemC and we would be effectively recreating SEAMS
from the paper. I thought SEAMS was a parallel simulator that supported
VHDL and later VHDL-AMS. Is this the same enviroment?
I would like to help create a mixed-signal environment.
Anyone else interested?
--Nathan