I was planning on a project that looks like fun and would help further my programming my abilities and what not. Its an led cube, I didn't see anything posted here from a search, but this is basically what it is: http://www.youtube.com/watch?v=tTfobw29-DM The idea is to have all the leds connected in a way so you can control each individual led at any individual point in time. The technique pretty much all of these cubes use is multiplexing, which each horizontal layer's cathodes are connected together, and each columns anodes are connected together. Here's where they explain it pretty well: http://www.instructables.com/id/STOHAYUFE7ITU56/ My question is, if I wanted to only light one led at a time, I need ground whichever layer its on, then output which ever anode. But for the grounds that don't need to be connected (the layers that don't need to be connected), would you enter some kind of tristate (really high input resistance) to simulate an open circuit? I'm going to be using a PIC μcontroller if it makes any difference, probably one of the newer 16bit ones. Is this possible with the PIC controllers? Sorry if this is really basic or doesn't make any sense lol.