Re: gEDA-user: Re: Silly PCB question?

[DJ Delorie <dj@delorie.com>]

> Sorry, I am not sure if I understood what the layers are. I
> understand that the board can have no more than two cooper faces
> (layers). At the left side of the PCB screen I can see several
> buttons (Solder, Gnd-Sldr, Vcc-Sldr, Component, GND-comp, Vcc-comp,
> unuesed, unuesed, etc.), but I think I should see only two, if each
> button represents a layer (cooper face) of the board.

PCb supports "layer groups" as well, where multiple colors correspond
to a single physical copper layer.  This is done only to aid the
developer in keeping track of the traces during development.

But in general, a physical board will have some number of copper
layers, almost always even (2, 4, 6 layers).  PCB supports up to 8
layers, and unless you tell it otherwise, it will assume your physical
board has 8 layers (or however many layer group possibilities are
configured, four in your case).  By deselecting the unused layer
buttons in PCB, you can tell PCB how many physical layers you want
your board to have.

> Also, when I "autoroute", I end with more than two colors of tracks.

Then you neglected to tell PCB to not use the other layers.