A firmware for the Atreus keyboard, written in Microscheme.

See this article about how it works.

• 6KRO (6 simultaneous keys, plus modifiers)
• Software debouncing
• Multiple layers, momentary and sticky (limited only by memory)
• Combo keys (a single keystroke can send a modifier and a non-modifier)
• Bind arbitrary Scheme functions to a key
• ~300 lines of code

This requires avrdude for uploading to the controller on the keyboard; install with your package manager of choice.

Replace /dev/ttyACM0 with the path your OS assigns to the USB bootloader of the microcontroller (on Mac OS X sometimes it is /dev/cu.usbmodem1411 or similar):

$ make upload USB=/dev/ttyACM0

By default you get the "multidvorak" layout, but you can also build a qwerty layout:

$ cp qwerty.scm layout.scm
$ make upload USB=/dev/ttyACM0

Or edit layout.scm to your liking; you can see a list of available keycodes in keycodes.scm.

The firmware can also be run on a PC rather than on the microcontroller in the keyboard using test.rkt which loads it up into Racket and simulates the GPIO functions with a test harness:

$ make test
racket test.rkt
..........................

The reset function has no effect; hard-reset (shorting the RST and GND pins with a wire) must be used to flash the firmware.

Copyright © 2014-2020 Phil Hagelberg and contributors

Released under the GNU GPL version 3.

Uses PJRC USB Keyboard library which is Copyright © 2009 PJRC.COM, LLC and released under the MIT/X11 license.