The Ploopy Mini Trackball is fairly easy to program and reprogram, thanks to the excellent work by all of the developers and maintainers of the QMK firmware suite. This guide will focus specifically on flashing firmware to the Ploopy Trackball.

If you have never used QMK before, go through all of the steps in the QMK guide to set up your environment.

QMK was built for keyboards, so you'll see lots of references to code that looks like the following:

-kb <keyboard>

Whenever you see that, use the following syntax:

-kb ploopyco/trackball_mini/rev1_001

and you'll be fine.

You only need to flash a bootloader if you're building a Ploopy Mini Trackball from scratch, or if your bootloader has become corrupted in some way.

Follow the steps in QMK's flashing guide. You may require hardware that we don't provide, such as an Arduino device.

You'll require the following fuse settings when programming the bootloader:

Fuse	Setting
Low	0x5E
High	0x99
Extended	0xC3

With your terminal window open and pointed at your QMK build environment, compile the firmware with the following command:

qmk compile -kb ploopyco/trackball_mini/rev1_001 -km via

Alternatively, you can invoke the Makefile directly with the following:

make ploopyco/trackball_mini/rev1_001:via

If you wish, you can use the default keymap (with qmk compile -kb ploopyco/trackball_mini/rev1_001 -km default or make ploopyco/trackball_mini/rev1_001:default). However, the VIA keymap is particularly interesting because it allows for customization of the trackball's functions without reflashing the firmware, through the use of the convenient VIA software package. It's incredibly handy, so definitely check it out.

For more details on building QMK firmware in general, see the QMK firmware guide.

Putting the Ploopy Trackball into bootloader mode is very easy.

1. Unplug it from your computer.
2. Hold the "forward" button. This is the button just to the right of the ball; it normally sits under your ring (fourth) finger.
3. While holding the forward button, plug the Ploopy Mini Trackball into your computer. If you're using QMK Toolbox, it should show up in the console. If using dmesg, it'll show up as an Atmel DFU device.

And that's it. While plugged in this way, the Ploopy Mini Trackball will accept new firmware.

Use your preferred method of flashing QMK firmware.

• QMK Toolbox has been verified as working.
• Using dfu-programmer from a terminal window has also been verified as working.

For more details, see the QMK guide on flashing firmware.

Unplug it, replug it in, and you should be good to go!

Happy customizing!