This is the code I run on my 3x3 macro-pad. The main reason I built it is to provide mouse click buttons next to my [Ploopy Nano](https://ploopy.co/nano-trackball/). I use the [maddie](https://github.com/qmk/qmk_firmware/tree/e7931289918221081cbe2a7ea5df27a5d86324db/keyboards/ploopyco/trackball_nano/keymaps/maddie) keymap which includes code that turns the Ploopy into a scroll wheel when num-lock is toggled twice in 25ms which is why one of the buttons is programmed to do that.
I 3D-printed the macropad using [this model](https://www.thingiverse.com/thing:4816077), used some left over Kailh midnight jade switches left over from other keyboard projects, hand-wired to a Raspberry Pi Pico. The switches are wired to GPIO pins 0 through 8 with 0-2 across the top row, 3-5 across the middle row, and 6-8 across the bottom.
