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gEDA-user: Symbol creation questions



Ok, I opted to add power pins to the symbol because the idea of having capacitors floating near the part struck me as odd :)

Some questions about custom components:

1- I copied the Atmega8-1.sym symbol and pasted it on a new page, and saved the new page as Atmega8-dan.sym. Why is my chip zoomed out in the add component preview window as compared to the original? I did a translate 0 before saving, and I made my zoom the same as the original before saving too. What else effects how it looks in the preview?

2 - I believe the docs recommend that things generally be snapped to the grid. How come this part's components ( pins, rectangle, ... ) aren't aligned to the grid?

Thanks for the help,

-Dan

John Doty wrote:

On Jun 5, 2006, at 5:28 AM, Stuart Brorson wrote:

Here are possible things you can do:

*  Redraw the symbol.  Yes, it's a PITA, but part of doing designs is
drawing symbols.

*  If the symbol has implied power pins (net= attribute), then just
stick your decoupling cap on the same schematic sheet and attach it to
your power net and GND.  To attach to the power net, just draw a net
from the cap, and then give the net a netname= attribute.

Another way is to draw a separate symbol for the power and ground pins, and then give it the same refdes as the powerless symbol. Now you can have a perfectly explicit drawing of power distribution, but avoid cluttering the signal flow drawing with that stuff. This works for most gnetlist back ends, but unfortunately not for spice-sdb.


Stuart, can this be fixed? Your spice-sdb gives the obscure "Invalid wanted_pin passed to gnet-nets [unknown]" error when it sees a duplicate refdes. The reason I ask is that I'm retrofitting my chip design to have explicit power distribution (ah, the joy of changing customer requirements ;-).

John Doty              Noqsi Aerospace, Ltd.
jpd@xxxxxxxxxxxxx