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Re: gEDA-user: moving slotting to pcb?
John Doty wrote:
On Jun 26, 2010, at 11:18 AM, DJ Delorie wrote:
A random thought occurred to me today - why does gschem do slotting at
all? Why does it care about footprints and packages?
There's no reason for it to. There's not even any reason to select part values. Putting these things into source schematics is a barrier to reuse.
For me it is a barrier to reuse, to have to figure out a 2nd time, what
values went into a tested circuit.
Another issue is that hierarchy plays poorly with slotting: it should be possible to split a slotted component across hierarchical blocks.
I'm pretty sure you opt for opening and closing brackets in different
source files as well.
But you may have your uses for this request in super-complex VLSI symbols.
Would it make
more sense, from a design flow perspective, to just send the symbolic
information to pcb and let pcb assign footprints and pinouts?
No.
1. The gschem->pcb is only one of the many flows gEDA supports. Please, please, please DJ, do not forget this.
2. For documentation, most will want the pin numbers, refdeses, values, etc. to match the board as built.
yes
That way, gschem does all the symbolic stuff, and pcb does all the
physical stuff. It would, of course, mean major changes to pcb to
handle "elements without footprints yet" and stuff, as well as mapping
multiple refdes's to single elements. Probably make power pin
management more complex too, unless we came up with a new way to
manage "hidden" pins.
No reason to change pcb. What we need is a schematic processor to sit between gschem and gnetlist. Expand hierarchy, assign slots and values, turn the source schematics into project schematics for both netlisting and documentation. This is a clerical task, not a graphical task, so the extra input could just be a table of some sort.
If it gets implemented like this, i.e. I have to feed a table to assign
values in a schematic,
I might become a hermit ;-) or go on searching for a new tool chain. For
me, the schematic
is the place where I see the logic of a circuit most clearly and know,
why a component is
there and what it means. It's the natural place to define it's spec
therefore.
With lots of identical components running these things through
processors and tables
may make sense, but if you have a bunch of amplifiers, voltage deviders,
filters etc.
where no single value resembles anything else, this is totally nuts.
I'd say pcb does the mechanical and ev. thermal stuff, the other physics
is handled with
side-notes on paper or simulators and for me input to the schematics.
Armin
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