Okay, so I was playing around with hex opcodes the other day, turning lowercase on and off, turning the calc off, displaying ascii chars, etc, but then I ran into something I wasn't expecting, my calculator (TI-84 plus) turned off and once I turned it back on, the screen was upside down... like literally as if you had turned it 180 degrees. I thought this was really awesome, but of course I reset the mem and ram because well it's not very fun to use upside down xD, I'd like to know if this is like a well doccumented thing? And if anyone knows what code could do this, say I would want to recreate it (maybe with a reverse option this time xD)I dont really remember the code I used, it had 4 or 5 lines of opcode

Yes.