Subject: RE: Related Question [Re: your question about digital variable access]
From: Ian Wilson (imw@antrim.com)
Date: Wed Mar 21 2001 - 12:11:18 PST
Jon Sanders wrote:
>
> Glad to hear this clarification as if we force users to add "connect modules"
> in their text it would as Martin stated be cumbersome and would likely be a
> point of contention from a user perspective. It certainly would not be
> intuitive
> and it would be a bear to teach this requirement.
I agree. I'm not trying to change the approach taken in the 2.0 LRM - just
looking for synchronization semantics (and additional mechanisms, if necessary)
to make it work.
>
> Since conversion models can convert digital to analog in a number of ways (with
> delays, rise and fall times, deal with X and Z, ....) what are you
> proposing this
> conversion be. I see that what Martin and Kevin proposed as essentially
> defining
> this semantics, or are you just taking a step back and in the end may end up
> with something like they have propopsed?
>
These are 'uninterpreted' conversions - there are no connect modules, and no
levels or transition times to specify. For example, if you write:
wire w;
real r;
analog r = w;
then (ignoring X/Z), r takes on the values 0 and 1 (not 0 and 5).
Note also that r changes discontinuously in the above example, so for it
to be usable in contributions, etc, you have to condition it:
wire w;
real r;
electrical out;
analog begin
r = w;
V(out) <+ transition(5.0 * r, ....);
end
The levels (0 to 5) and rise/fall times are provided by the user
explicitly in the behavioral code here, and are not related to any
connect module or discipline.
--ian
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