Re: Visual SNL

[kerstien@odin.atdiv.lanl.gov (Deb Kerstiens)]

Greg Domer of Allied Signal kindly took the time to reply to my
request for information about using a graphical tool they use for
designing state sets.  I have included the information below.

deb

--Greg wrote:-----------------------------------------------------------

The package that we use is indeed called StateCad.  It is from a company
called Visual Software Solutions in Coarl Springs, FL.  Their website is
www.statecad.com.  StateCad is a state diagramming tool that is normally
used to develop state machines using hardware.  After drawing your state
diagrams, the software will generate the state equations in a high
definition language.  You have a choice of ABEL, VHDL, Verilog, and C to
name a few.  We chose ABEL because of the similarity between it and SNL.
Then we use a filter program that Dick wrote which will take the ABEL
output and convert it to SNL, minus some of the channel connections,
defined constants, function calls. etc.  So you see there is some work
involved translating from one to another.  StateCad provides error checking
for unused states and dead-end states, plus it becomes a valuable piece of
documentation when you go to debug your state sets.  There are several
limitations to using StateCad, but overall it should reduce development
time, because your state sets are more likely to be correct if they pass
the StateCad edits.

The code that Dick wrote was developed in Visual C++ and would be available
to anybody who would want to improve it.  Right now the whole process was
set up to provide a way of graphically designing the state sets, which
provides error checking on the state sets, and to bypass some of the
tedious work involved in creating the SNL.

We are currently using StateCad 3.10.  Version 4.10 has just been released,
but I haven't upgraded yet.  Sometimes the ABEL code looks a little
different between releases and we have to tweak the conversion  program.

-------------------------------------------------------------------------