For backlight control you should look into wiring a separate GND wire for the leds and having an n-channel FET control this GND connection.
Starting a thread for this to keep the main channel tidy
If you are designing a PCB and need to control a lot of LEDs you are better off adding a dedicated LED driver chip like the DM13A to your design and having that manage the LEDs for you. Mobiflight sees it as an output shift register.
For backlight control you should look into wiring a separate GND wire for the leds and having an n-channel FET control this GND connection. Starting a thread for this to keep the main channel tidy If you are designing a PCB and need to control a lot of LEDs you are better off adding a dedicated LED driver chip like the DM13A to your design and having that manage the LEDs for you. Mobiflight sees it as an output shift register.