My question is, what's happening to my arduino if it's pushing 5v out pin 0, and also receiving it in? Someone told me that LEDs only close the circuit when the potential difference between the cathode and the anode is greater than X volts. In this case it should be 5v on both sides, so maybe the circuit doesn't open?
when the pin is low your sinking current through the chip to ground, when its high its not really doing anything, as a LED is a diode and only lets juice flow from one direction
5v -> 560 ohm resistor -> led -> digitalPin 0I can turn the LED on by digitalWrite(0,LOW) and off by digitalWrite(0, HIGH).
I have an LED I hooked up mentioned above. I can turn it off by setting the pin LOW (short to ground). I can turn it on by setting the pin HIGH (short to 5v).
Semi-related, what would happen if I hooked 5V directly up to a digitalPin in output mode set to HIGH.