+ | PB11 PA8 | IR remote control output (via optocoupler, negated)
+ | RESET PB15 | MOSI2 - LED driver data input (via optocoupler, negated)
+ | 3.3 V PB14 | MISO2 - unused
+ | GND PB13 | SCK2 - LED driver clock (via optocoupler, negated)
+ | GND PB12 | SS2 - unused