The KC60 has breakout pins to which one may wire a strip of WS2812-compatible LEDs.
By default, the source is set up for 16 LEDs on the F5 breakout pin. See included image for wiring reference. If you attach a different number of LEDs, configure your source for the correct number of LEDs by adding a config.h file alongside your keymap.c file, with the following contents:
#pragma once
#undef RGBLED_NUM
#define RGBLED_NUM <number of leds>To enable RGB Underglow, simply add a rules.mk file containing RGBLIGHT_ENABLE = yes alongside your keymap.c file, and compile as normal:
make kc60:<keymap>The ws2812 keymap may be copied and used as a starting point.
RGB Underglow is a fairly large feature, and your firmware may be too large to be flashed with it enabled. Adding CONSOLE_ENABLE = no or COMMAND_ENABLE = no to your rules.mk file will reduce the size of the firmware greatly, and if you don't use either feature, is a very low impact change.
