I've hooked up my arduino to a 7 segment display with a common anode..
At first I thought it wouldn't work at all because I was setting the pins on the cathode side of the LEDs to high.. then I discovered when I set the pins to the cathodes high the LEDs turn off..
Which is good, because I just needed to do a binary NOT (pretty much) on the output.
However, I don't really understand what's going on.. when the cathodes aren't set high, how is this the same as them being ground? Can someone please tell me what's going on here? I don't quite see how the circuit is complete..