RE: Clarification question on port direction

Geoffrey,

I am not sure that I know what "signal-flow models really are, but
if I understand it correctly from the replies I got so far, the
direction makes only sense for digital ports, and not for
analog electrical ports.  If this is true, could we put something
into the LRM to state that for analog ports (if they exist) we do
not need to (or should not) use the direction declarations?  After
all, if tools ignore it, and if it is meaningless, why require them?

Also, if the order of the declarations is important, we should
perhaps mention that too in the LRM.  One of the two tools we
tried will take them in any order, but another one would give
errors.  Which one is correct?

Thanks,

Arpad
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-----Original Message-----
From: geoffrey.coram@analog.com [mailto:geoffrey.coram@analog.com] 
Sent: Monday, May 15, 2006 11:38 AM
To: Jonathan David
Cc: Muranyi, Arpad; VerilogAMS Reflector
Subject: Re: Clarification question on port direction

The "direction" has meaning for signal-flow behavioral models,
but I tried to make the point in my BMAS presentation for
compact modeling that "direction" does not apply to resistors,
diodes, transistors, etc.

Jonathan sort of made that point when he noted that logic gates
do have a "direction."

Many analog simulators do not, in fact, differentiate between
input/output/inout.  (I will also note that you had the order
backwards in your post, relative to how one simulator "requires" it:
you should have 
  inout p, n;
before
  electrical p, n;
)

-Geoffrey



Arpad Muranyi wrote:
> If so, I would also like to get some help in determining what
> makes an analog port input or output.

Jonathan David wrote:
> 
> In Reality It should make little difference to the
> behavioral model.