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Mail Archives: geda-user/2015/07/03/15:00:12

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Date: Fri, 3 Jul 2015 14:59:59 -0400
Message-Id: <201507031859.t63IxxSd028833@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: geda-user AT delorie DOT com
In-reply-to: <alpine.DEB.2.11.1507031640470.13761@nimbus> (message from Roland
Lutz on Fri, 3 Jul 2015 16:56:21 +0200 (CEST))
Subject: Re: [geda-user] Language conventions: component vs. package vs. device...
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> While refactoring gnetlist, I've encountered a few quasi-synonymous terms 
> which seem to refer to subtly different concepts:
> 
>    component <-> device <-> netlist <-> package <-> symbol
> 
> Not being a native speaker, I'd like to ask you what you mean when using 
> these terms, and what you understand to be the difference between them.

There are some definitions (which may be gEDA-specific) in the PCB
Getting Started Guide:

http://www.delorie.com/pcb/docs/gs/gs.html#Terminology

In general, we differentiate among:

* A symbol, which may be re-used many times within a schematic
* A footprint, which may be re-used many times within a layout
* A model, which may be... you get the point
* A component, which represents one unique object in the project

A component/device/part would link one or more symbols in the
schematic to a model in the sim or an element in the layout, and
possibly convey more information like manufacturer's part number,
cost, etc.

In PCB, we further have an "element" which is a footprint plus
component-specific information (it's a footprint in the library, and
an element in your layout).

> Also, what's the difference between a pin and a net, and between a uref 
> and a refdes?  (If it's the same thing, why are there two different names
> for it?)

A "pin" is a single logical electrical connction to a component.  In a
schematic, this is represented by a net connection to a symbol.  In a
layout, this is represented by one or more metal connection points.
In a simulation, this is represented by a parameter to the model.  Etc.

A net is a collection of connections between pins.  A netlist is a
collection of nets.

I think uref == refdes, just different names because different people
wrote different parts of the software.

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