On Sun, Mar 01, 2009 at 01:46:40PM +0100, Stefan Salewski wrote: > On Sat, 2009-02-28 at 16:51 -0800, Ben Jackson wrote: > > I just spent a couple hours debugging a half-broken AVR microcontroller > > which was due to me putting GND and "UGND" (USB GND) far apart on the > > symbol and forgetting to connect GND. > > Sorry, I can not really see the conclusion of your message. > > UGND pin for USB should be near to the other USB related pins, I think.
Right, that's why I put it there. I just happened to put the GND pin on another corner and missed connecting it. I made the symbol at most a day before I drew the schematic and still managed to forget it. > http://www.gedasymbols.org/user/stefan_salewski/symbols/AT90USB1287-3.sym Mine is similar to that. > Would you suggest to modify the symbols? Well, in my case I am realizing that I made a symbol that led me to miss connecting a pin. I'm trying to learn from it, by keeping in mind that if I put a must-connect pin next to a dozen "can connect" pins (port IO in this case) I am more likely to miss it than if I put it in with all the other must-connect pins like power, clock, config, etc. I also assume that if I'd been more careful and used my explicit "NC" symbol (a "graphical=1" symbol with a pin going to an "X") I would have noticed if I'd tried to NC a GND. And finally if I'd used the gnetlist DRC it might have squelched about the NC pin. > Some people prefer symbols identical to package shape , this is > available too: > > http://www.gedasymbols.org/user/stefan_salewski/symbols/AT90USB1287-1.sym I made a symbol like that for a big FPGA. In that case I used 'NET' attributes to tie all the grounds and VCC and left only the IO pins. It was an old enough FPGA to be single voltage, though. Another sheet I saw pulled all the power and GND pins out and floated them in the middle of the big box symbol so they were still explicit but easily connected with a single wire. Hiding them all around with the IO seems like a great way to miss them. -- Ben Jackson AD7GD <b...@ben.com> http://www.ben.com/ _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user