- I upload a blank sketch: pin 13 LED is on. Why?
- I connect pin 13 to GND: it turns off until I remove the connection
- I connect multimeter between pin 13 and GND: measures 0.14V and LED turns off until multimeter is removed
- I press hard reset: LED blinks a few times, turns off for a second then turns on
- I upload a sketch that on setup sets pinMode(13, INPUT): pin 13 LED is on
- I upload a sketch that on setup sets pinMode(13, OUTPUT): pin 13 LED is off 0.01V
- I upload a Blink example: Everything works fine, LED cycles from 4.84V to 0.01V
Why is the LED on unless I set pinMode to output? Have I broken my UNO or is this normal? I swear it wasn't like this a few days ago.