I've just tracked a board with multiple grounds and hit the same problem. I simply created multiple ground planes, and star connected them back to the incoming earth lead. However, it was rather fiddly making sure I didn't make an erroneous connection to one of the planes, something which wasn't helped by Kicad mixing up DGND and AGND in PCBNew. I don't know if there is a better way (though a zero ohm link sounds like a cunning idea).
Regards, Robert. Anders Gustafsson wrote: > Hi! > > I am layouting a L297-based, chopped, unipolar stepper driver. The > steppers are rated 20A max, consequently, switching 10-20A into an > inductive load creates quite a bit of noise. > > The problem I am seeing is not uncommon for chopped steppers, ie that > the chopper settles on a subharmonic of the switching frequency > (20kHz) because of crosstalk. > > I have tried moving stuff around on the prototype board and looking > at various grounding strategies. I have separated AGND and DGND in > the schematic and then joined them, but that makes KICAD treat them > together as a net. What should I do? Put in a 0 ohm resistor where I > join them to keep filled zones separate? > > Any ideas, tips, pointers? > > (Apologies if this appears multiple times as Yahoo seemed to have > problems this morning) > > > > > > > > > > > > > - Anders Gustafsson Engineer, CNE6, ASE Pedago, The Aaland Islands > (N60 E20) www.pedago.fi phone +358 18 12060 mobile +358 40506 7099 > fax +358 18 14060 > > > > > > ------------------------------------ > > Please read the Kicad FAQ in the group files section before posting > your question. Please post your bug reports here. They will be picked > up by the creator of Kicad. Please visit http://www.kicadlib.org for > details of how to contribute your symbols/modules to the kicad > library. For building Kicad from source and other development > questions visit the kicad-devel group at > http://groups.yahoo.com/group/kicad-develYahoo! Groups Links > > > > ------------------------------------------------------------------------ > > > > No virus found in this incoming message. Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.64/2320 - Release Date: > 08/22/09 18:04:00 >
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