The short version: in function rgb_matrix_indicators_kb() in file keymap.c, use function rgb_matrix_set_color(). For example, to set a blue colour on key F7 on a Keychron V5: Introduction It isn’t well advertised in the QMK documentation or any examples you may …
Setting RGB colour for individual keys in QMK (per-key RGB colour) Read more »
The short version: Use QMK‘s send_string_with_delay() with binary content (as it is not a real string) encoded in a particular manner to piecemeal execute a macro, housekeeping_task_user() to run a state machine for executing the macro (which can check for …
The basis for a way to cancel QMK macros in progress Read more »
For example, the total number of key actions available to macros defined in Via can be increased from about 150 to use most of the free flash memory, using emulated EEPROM memory (or possibly be limited by the RAM (used …
dfu-util can be used to both read off and to flash (update) firmware on embedded devices, say for the firmware on a QMK-based keyboard like the Keychron V5 (about 50 KB). But it is very poorly documented. In most cases, the …
Flash utility ‘dfu-util’ gotcha: Always use option ‘-a 0’ Read more »
The short version: The CAN bus 2 channel on ARM microcontrollers only works if CAN 1 is also set up… That is, CAN 2 can not be set up independently; for it to work at all, the other CAN channel, …
Gotcha using CAN 2 on ARM microcontrollers (e.g., STM32F415 on 1Bitsy) Read more »
The short version: Two external pull-up resistors of 10 kΩ on the PS/2 DATA and CLK signal lines (corresponding to USB signal lines D- and D+, respectively) are sufficient to interface to a PS/2-capable USB keyboard. Say, to get a macro …
The short version is that a 17 ms delay between each key action (press or release, normal key or modifier key) for an Arduino-based keyboard will solve most problems. At this point, there isn’t any known solution for USB 3 ports, …
Blues typing out fixed texts on both QMK and Arduino Leonardo-based macro keyboards Read more »
The short version is: Download the tar ball from arm.com, extract, add the /bin folder in the extracted to the path, and make GDB work by adding symbolic links in /usr/lib/x86_64-linux-gnu for the expected version 5 of the libraries “libncurses” …