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Re: gEDA-user: input/output ports gschem

Hi,

How the attributes (including net attributes) are handled
mostly depends on the particular backend netlister's format
reqirement and choice of implementation. Each backend's
usage of attributes may be different from the other; although
there are some common usage of certain attributes among all
backends.

Documentations of attributes usage for any particular backend
netlister are in the Netlister section of:
  http://geda.seul.org/wiki/geda:documentation


Best Regards,
Paul Tan



-----Original Message-----
From: Felipe De la Puente Christen <fdelapuente@xxxxxxxxx>
To: gEDA user mailing list <geda-user@xxxxxxxxxxxxxx>
Sent: Thu, Apr 15, 2010 6:29 pm
Subject: Re: gEDA-user: input/output ports gschem


Many thanks for the info!

The example about hierarchy design using ports, was pretty useful John.

On the other hand, I see that instead of applying a netname to every
signal connected to an i/o port, I just have to add the pinnumber/label
to the net= attribute of the port(The link was very useful Duncan,
didn't see it surfing on the wiki brefore).

So, now I know how to do it. BUT I feel like gschem could consider
net=SIGNALX to be an implicit form of net=SIGNALX:1 since specifying a
pin in a one pin symbol doesn't make much sense to me. I think this is a
very simple feature to implement. Would be great if it does so.

Best Regards, Felipe.

--
Felipe De la Puente Christen
Mobile Phone    : +56 9 93199807
MSN/GTalk       : fdelapuente@xxxxxxxxx


On Thu, 2010-04-15 at 14:25 -0600, John Doty wrote:

On Apr 15, 2010, at 1:06 PM, Felipe De la Puente Christen wrote:

> Hi,
>     I did a design using input, output, and io ports based on the
> input-2.sym available in the library. I thought that the net 
attribute
> would make the net between the component's pin and the port to be 
named

> the same as the port's net attribute, but I was wrong and it's still
> necessary to put a netname on the nets involved to make the logical
> connection at the other side(another port + net + component's set).
>
>     So the question(suggested by DJ) is: How are these input/output
> graphical ports supposed to work? Are they merely graphic things, 
or

> does that net attribute have a special/useful function?
They are for hierarchy, not for making connections between sheets at 
the same
level.
For connecting sheets at the same level, the netname attribute is the 
thing to
use. For clarity, I like to group such connections into busses (which in gschem 
are just graphical).
For hierarchy, match pinlabel on the symbol representing the 
subcircuit with
the refdes an the connection symbol within the subcircuit schematic.
Here's a fragment of such a design. In particular, look at the 
DACtoClock
block on sheet 2 to see how hierarchy works, and the connections between sheets 
1 and 2 for usage of netname and busses.



John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx






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