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Re: gEDA-user: A component cannot contain another component?
Peter Clifton:
> On Sun, 2009-11-01 at 13:09 +0100, Karl Hammar wrote:
> > [1] says so:
> >
> > component
> > Valid in: Schematic files ONLY
> >
> > ///
> >
> > But if create:
>
> Sounds like a bug...
Bug or not.
[2] specifically says:
Can my local library cover frequently needed sub circuits?
Yes, symbols can contain symbols and nets.
So [1] and [2] are in conflict with each other.
> we should be rejecting things like that in case
> anyone finds some strange unintended behavior, then starts to rely on
> it in a way which precludes us doing something different in the future.
Ok, are there any plans for the future, or can we shape them here?
A good plan would be to accept and to be able to use symbols in other
symbols, just like the above. Inheritance and recursion are good
and well understood software concepts which could very useful in this
context also. And I consider this "unintended" behavior good, and
that "residual" bugs should be eliminated.
> Specifically, regarding why this is a bad idea.. I suspect the
> net-listing of such nested components inside symbols will not work
> properly.
It does not sound like a description of why this is a bad idea,
it sounds more like the question if the bug is in the documentation
or if it is in the code.
> There are already ways to do sub-circuits and hierarchy in gEDA, so
Good to hear, but then why don't they show up when I do [3].
> unless there is a good reason, I'd suggest sticking to those.
Yes, I do think there are good reasons, though I am rather new to gEDA
so I cannot give much comments of the other ways.
The ways in gEDA I can find are [4-6], which seems to be more of
workarounds than real solutions.
There seems to some requests that could be solved with
sub circuits ([7,8]).
The good reasons and examples I can thinks make up right now are:
. it is a natural concept readily understood
. it would be useful and could better solve case [4-6]
. a sub circuit (+its pcb layout) can solve tricky problems for reuse
. they can be optimized and separately simulated
e.g.
. I could make a microproc/sram/flash/ethernet sub circuit symbol+footprint
and simply add different io-parts for different projects
. I could have an "active filter" symbol, ready and optimized (incl.
the pcb layout) and just drop it in place
Sub circuits are not new, why do people do IC and such?
Well, to solve a common problem "once and for all".
> Was there something specific you were trying to achieve by inserting
> components in a symbol file?
Yes:
. to demonstrate that is was possible, maybe not intentionally
implemented and maybe not fully functional, but possible
. to start a discussion about it
. to find the "remaining bugs"
. to make it a good feature of gschem/pcb
Regards,
/Karl
[1] http://geda.seul.org/wiki/geda:file_format_spec?s=file format
[2] http://geda.seul.org/wiki/geda:faq-gschem#can_my_local_library_cover_frequently_needed_sub_circuits
[3] http://geda.seul.org/wiki/?do=search&id=subcircuits
[4] http://www.seul.org/pipermail/geda-user/2009-October/021268.html
[5] http://www.seul.org/pipermail/geda-user/2009-October/021282.html
[6] http://www.luciani.org/geda/util/matrix/index.html
[7] http://www.seul.org/pipermail/geda-user/2006-July/000251.html
[8] http://www.seul.org/pipermail/geda-user/2009-October/021281.html
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Karl Hammar Aspö Data karl@xxxxxxxxxxx
Lilla Aspö 148 Networks
S-742 94 Östhammar +46 173 140 57 Computers
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