I know that the pi can't produce those values, but not only did my company provided, just calibrated, professional grade multimeter say the -3v3 when connected normally, the circuit itself corroborated this. I've made painstakingly sure to change nothing on the circuit except where the positive and negative leads plug into my board (which is to say I left the jumper on the GPIO pins, and moved only where they connected to my breadboard).
Before the reset the circuit would only work with the GPIO acting as ground and the ground acting as 3v3. It was weird but it worked. After the reset, the circuit was no longer working. I swapped only where the jumpers plugged into the breadboard. You can see the circuit itself in the photo (and yes the red wire is the anode for the LED
) red wire went from GPIO 23 to + rail, green jumper went from plus to pin 1 of uln2003, blue jumper goes from pin 8 (ground) to - rail, black wire goes from - rail to ground. On the high side my white wire went from 5V to the + rail, jumper trough a 330 ohm resistor to the LED's anode, LED's cathode connects to pin 16. When GPIO 23 goes high it completes the circuit allowing voltage to flow through the LED.
It's a *painfully* simple circuit that would not work before the reset without the red wire (GPIO 23) being plugged into the - rail and the black wire (ground) into the + rail. After the reset it wouldn't work again until I returned the wires to their original locations.
I'm sorry for harping on this so much, but I want to make it explicitly clear that I fully ruled out user error (in so far as the circuit is designed at any rate). I've yet to remove the jumpers from the GPIO pins to the breadboard from the GPIO. I did all my testing through the wires. It's literally impossible for me to have connected to the wrong GPIO and then fixed it latter because I'm still connected to the original GPIO!
I also get the fact that it's impossible for the pi to put out -3v3, so we're faced with two impossibilities and while I'm also prone to believe that the impossibility that relies on the infallibility of a man is the one to put your money on for having actually made a mistake, I can also fully confirm that it was working before a reset, I reset, it didn't work, I swapped nothing more than the + and - rails to what they should have been all along and it worked again and my multimeter confirmed a +3v3 from pin 23 to ground.