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Date: Wed, 11 Jul 2018 16:21:29 +0200 (CEST)
From: Roland Lutz <rlutz AT hedmen DOT org>
To: "Rob Butts (r DOT butts2 AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Subject: Re: [geda-user] How to define for an exposed pad to connect to 3
 pins/pads
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On Wed, 11 Jul 2018, Stephan Böttcher wrote:
> NB, I was wondering about corner cases.  Say, a symbol has atttributes
>
> net=GND:7
> net=VCC:14
>
> In the schematic I promote one of them, and add a third
>
> net=V33:14
> net=nOE:1
>
> Is there a formal rule that ensures that the net=GND:7 in the symbol is
> accepted, but the net=VCC:14 is not?  Or do I need to always promote all
> net= attibutes if I attache any to the symbol instance?

Attribute propagation for net= attributes works a bit differently than it 
does for other attributes:  For each pinnumber, the netname given by 
attached net= attributes (including promoted ones) overrides the netname 
given by inherited net= attributes.  So, in your example, the "net=V33:14" 
attribute overrides the "net=VCC:14" attribute, resulting in pin "14" of 
the component being connected to net "V33".

You don't have to promote net= attributes which you don't intend to change.

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