qmk-firmware/keyboards/ploopyco/trackball/rev1

See the main readme for more details.

This is just the rev 1.001-1.004 trackball

Programming QMK-DFU onto the PloopyCo Trackball (Advanced)

If you would rather have DFU on this board, you can use the QMK-DFU bootloader on the device. To do so, you want to run:

make ploopyco/trackball:default:production

Once you have that, you'll need to ISP Flash the chip with the new "production" hex file created (or the production hex), and set the fuses:

Fuse	Setting
Low	0x52
High	0x99
Extended	0xCB

Original (Caterina) settings:

Fuse	Setting
Low	0xFF
High	0xD8
Extended	0xFE

If you're using QMK DFU, you'll also need to add BOOTLOADER=qmk-dfu to your keymap's rules.mk file, to ensure that the reboot/reset works correctly. Otherwise, it will jump right back into the firmware, like nothing happened.

Additionally, once you've flashed the qmk-dfu bootloader onto your device, you will no longer be able to use the Arduino IDE to flash the board. You'll need to use the command line or QMK Toolbox to flash it.