Arduino for STM32

I have added Switch controller emulation to my massive GameCube controller adapter project: https://github.com/arpruss/GameControllersSTM32

The project now lets you use a GameCube controller and/or a Wii Nunchuck as an XBox360 controller, a variety of various binds of standard joystick based controllers, a keyboard, or, now, a Switch controller.

In Switch mode, you get all the 13 buttons of the Switch Pro controller, except that some require shifting (the shift key is Z, though you can edit the mapping easily; so, e.g., START = + but Z+START = -).

Hi and thank you for this great job. Is it possible to have a working example with the switch mode. I would like to make my own Gamecube controller to switch adapter.
The pin that need to be connected to the STM32 is the data port and GND port that's right ?

Thanks