This is my first custom keyboard, a 5x5 cherry mx matrix based on the STM32F1 with libopencm3. The project contains firmware, schematics and a board layout in kicad.

This project is intended as a platform for custom keyboard development. It supports:

• usb keyboard scancodes
• bios boot and nkro
• system / consumer codes
• generation of mouse events
• usb serial interface
• an automouse mode for fast-clicking
• programmable macro keys via serial
• storing current configuration in "userflash"

The board is programmed using a 6-pin TagConnect, that must be wired to a STM Discovery SWD/STLink programming port.

git submodule init
git submodule update
make -C libopencm3
make

The board provides 3 types of keyboards via different usb endpoints.

1. The first is the usb standard bios keyboard definition, which allows the keyboard also to emit key codes to hosts with limited usb hid support. (This used to be the case in <2015 style bioses, hence the name.)

2. The second keyboard is a n-key-rollover, which exposes a keyboard that allows 224 usb keyboard scancodes to be pressed simultaneously. Also, because we do not need to adhere to the bios boot standard, this endpoint's interval can set much lower = it types much faster.

3. The third keyboard can emit so called consumer and system codes. Example consumer key codes are PLAY, PAUSE, but also MARK, CLEARMARK, REPEATFROMMARK. So everything the typical multimedia keys emit and then some.

Operate the rodent from your keyboard! There is support for x, y, 5 buttons and a vertical and horizontal scrollwheel action.

The board exposes a serial port for logging, and configuration. Commands available are:

? - show a terse description of available commands.

i - show usb info strings; contains the git-describe tag of the
    current firmware, so mission critical to some, useless to
    everybody else.

d - dump the keymap(s).

K - redefine a key in the keymap, takes a hexadecimal argument of
    the form <layer><row><column><type><arg1><arg2><arg3>, with each
    argument being 2 digits long.

m - clear all macro keys.

M - define one macro key, takes an argument of the form
    <number><oftenusedstring>. The number is a two hexdigits, the
    string can be upto 32 7-bit ascii chars long and is terminated
    with a newline.

n - set keyboard mode to bios (default).

N - set keyboard mode to nkro.

R - read configuration from flash

W - write configuration to flash

Z - clear the configration flash, revert to "factory" keymap at
    next powerup.

Command interpretation starts after receiving a newline.

Automouse is a mouse clicker, with optional speed setting and wiggle amounts. This allows you to click real fast, and wiggle the mouse while using your hands for something else.

Macros set via serial are lost at power off unless the configuration is written to flash. Loading from flash happens automatically at powerup.

The strings that you provide via serial need to be translated into usb keycodes, so currently only 7-bit ascii strings are supported.

Setting macros via the shell is easy:

echo -e "\nM01Nevergonnagiveyouup!\n" > /dev/ttyACM0

Notes:

• The initial newline is a trick to make sure our M will be considered the start of a command, no matter what has been put to the serial before by you, some driver or the os.
• This particular example defines the macro for macro key number 1.
• You need to have a macro key 1 in your keymap, otherwise you have nothing to trigger the macro.