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Date: Fri, 5 Feb 2021 22:21:17 +0100 (CET)
From: Roland Lutz <rlutz AT hedmen DOT org>
To: "Nicklas SB Karlsson (nk AT nksb DOT online) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Subject: Re: [geda-user] Power and IO symbols
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On Fri, 5 Feb 2021, Nicklas SB Karlsson (nk AT nksb DOT online) [via 
geda-user AT delorie DOT com] wrote:
> Den 2020-12-09 kl. 00:18, skrev Roland Lutz:
>> The symbols are functionally equivalent (each symbol has a netname= 
>> attribute which specifies the net to which it is connected, visible by 
>> default for all but the ground symbols), they only differ in their 
>> visual representation and can be used interchangably.
>
> All voltages are the same. Think it make sense only these with the same 
> symbol is connected to same net and there is a need for several 
> voltages. In my schematic I have more or less globally 3.3V, analog 3.3V 
> and 5V. But also have 24V which is very common for automation equipment.

With these symbols, you can select which net they connect to by changing 
the netname= attribute.

If you use pwr-1.sym as is, it will connect to the 3.3V rail; but if you 
change it to netname=+5V, then it will connect to the +5V rail.

> Might also make sense only these ground with same symbol belong to same net.

Which symbol you use only changes the visual representation; the net is 
determined by the netname= symbol.

> Logic ground and and protective earth ought to be rather common and 
> maybe also analog ground. Sometimes circuits are isolated but these are 
> local or less global.

There are various conventions as to which symbol indicates what, and how 
to call the "ground" net, so I think this is best left to the user.  The 
default is netname=GND which is in accord with gEDA/gaf conventions.

> Looking in my schematics I have refdes and it produced more or less 
> useful circuit boards, or at least the sub schematic was connected.

Yes, that works as well, but it makes it easier to shoot yourself in the 
foot as the connections aren't (can't be, actually) checked.


On Fri, 5 Feb 2021, Nicklas SB Karlsson (nk AT nksb DOT online) [via
geda-user AT delorie DOT com] wrote:
> Den 2020-12-09 kl. 14:33, skrev Roland Lutz:
>> Pro: The confusion between netname= and portname= is resolved by 
>> actually making it the same thing.
>
> No do not think so then sub schematic is instantiated more than once, 
> or?

What makes you think so?


Roland