Re: gEDA-user: Slotting and visible power connections

["Bernd Jendrissek" <bernd.jendrissek@xxxxxxxxx>]

On Wed, Nov 5, 2008 at 8:06 PM, Joerg <joergsch@xxxxxxxxxxxxxxxxxxxxx> wrote:
> When you place, say, a LM324 as the seventh chip it will plop down U7A.

What do you mean "place ... as the seventh chip"?  Do you mean when
you place your 25th opamp symbol that happens to be realized as 1/4 of
a LM324?

How does Eagle deal with, say, a "7464: 4-2-3-2-Input AND-OR-INVERT
Gate" (randomly picking from a 7400-series list)?

> Only U7A, U8A and so
> on have power pins.

Why?  What's so special about the "A" slots?

> If you pick a device with implicit pins and suddenly
> find out "Oh, I better filter that chip over there separately" you click
> an invoke tab and the hidden power pins show up on the -A slot. But only
> for the device you click after invoke, not all of them.

Hmm, how do you prevent yourself from doing incompatible things with
the various slots' power supplies?  Say, for example, that in one part
of your schematic you have an opamp where you use the power pins as
outputs, but in another part of the schematic far far away, you're
filtering the power supply?

Are the hidden power pins always there but not visible?  In another of
your replies it seems like Eagle is adding a *separate* power symbol
on top of the opamp symbol, judging by the "U7P" refdes that gets in
your way.

I guess I don't "get" what this "invoke" tab is.  Can you send me a
screenshot (privately) - maybe that will help me understand?

> When you renumber it leaves those instantations intact, if you don't let
> it then it will not swap, for example, U7C with U8A. This is important
> for situation where some not-so-orthodox compensation scheme relies on
> the fact that circuits are on the same die.

Heh, I wonder how this would affect gate-swapping back-annotation.
The PCB layout tool would have to be smart enough to know that SOME
identical-looking gates/opamps can be swapped, but not ALL.

elsewhere you wrote:
> That could quickly lead to an island solution where there is no way back
> to where everybody else is.

It sounds worse than it is; yes it takes work to merge the forks again
after a period of divergence, but it isn't like speciation in nature
where there's no way back.  I've managed to keep my fork(s) in sync
with the mainline code so far.  (This isn't a symmetric relation,
though.)


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