Re: gEDA-user: blue sky ideas - written down finally

[DJ Delorie <dj@xxxxxxxxxxx>]

> family symbols might be a good concept.  it's a medium weight symbol
> for a family of parts.  e.g. an FPGA family, or uC family, or is this
> still a light symbol?

For example, resistor-1.sym, resistor-2.sym, and resistor-3.sym are
all variants on symbol class RESISTOR.  A 7400's gate symbol could be
a NAND gate, or an OR gate with inverted inputs.  Both symbols would
be variants of the NAND symbol class.

The idea is to let you right-click on a symbol and select alternate
graphical representations, without actually changing the symbol
(i.e. and having to re-add attibutes, etc).

> [(A,B),Y]=[1,2,3], [4,5,6], [9,10,8], [12,13,11]
> 
> I think that this simplified down to the required parts.

I suppose some of the syntax can be defined as "optional" and implied,
if we can guarantee that it's deterministic.

I can imagine cases where pins can be swapped on some of the gates,
but not all, for example an FPGA where some pins are input only, or an
MCU where some UARTs are less configurable than others.  Let's define
the swappability as a property of the chip, not the symbol, so parens
on the left are migrated to the corresponding pins on the right - then
if you have parens only on the right, you have the ability to define
swappability on a per-gate basis.  I.e. your example is changed to
this internally:

  [A,B,Y]=[(1,2),3], [(4,5),6], [(9,10),8], [(12,13),11]


>   GND=7
>   VCC=14
> 
> These need some marking to denote that they are like "net" connections
> not virtual pins, meaning that they are not on a standard symbol, vs
> assuming that if there is no pin than it is a net like connection.

No, they don't.  If they don't show up elsewhere (like in a symbol),
they need to be connected some other way.  This also means that unused
gates show up in that "other way" - giving you an opportunity to tie
them to something.  We don't need to *say* they won't show up on a
symbol, because we can determine that programmatically - and by not
making them special, we still allow for "power symbols" that have only
those two pins.

> This seems to cover most bases, but you made no mention for mapping
> mappings to physical, or did i miss something in the database stuff?

Pin numbers/names on the right side correspond to the numbers/names of
pins/pads on footprints.  So, choosing a package change which mapping
you use, so that it corresponds to the physical pinout of that
package.


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user