kicad-developers team mailing list archive

[Lorenzo Marcantonio <l.marcantonio@xxxxxxxxxxxx>]

On Thu, Jun 05, 2014 at 01:15:31PM -0400, Jean-Paul Louis wrote:
> 	1 - The jumper layer to me is redundant with the component layer as a jumper can be
> 	described as a component, a socketed IC, a heat-sinked device or a multipart connector can be
> 	treated as a compound component (module).

'Jumper' is a kind of layer for SPECCTRA routing purposes; it's not for
pcbnew consumption (I presume it tells the router: hey, you can go thru
there but it's very expensive and only for short straight lines).

> 	2 - To me, the courtyard concept is part of the footprint, so it doesn’t need a layer. 
> 	It is only used for placement purpose (design rules) to carry manufacturing assembly
> 	constraints (its shape should be arbitrary).

And footprints are made up from entities living on layers. So it needs
to be a layer :P

> 3 - Is the fact that the Layer ID goes from 0 to 16 or whatever so important that it cannot be changed?
> 	I mean the sequential aspect of the ID number.

Pretty much important. There are a lot of for loops enumerating copper
layers and you would need some operator magic to keep them working.

> 	If so, why not use 0 to 127 for the copper layers, and 128 to 255 for the other layers?
> 	That would still fit in one byte if byte is the limit, and I have yet to see a board with more
> 	than 128 layers.

The problem is not the layer number in itself... there are bitmask with
one bit for layer, so it's not trivial to go over 64 (number of bits in
a uint64_t). It can be done, it's only more difficult (to do it
efficiently).

-- 
Lorenzo Marcantonio
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