Timed function layer keymap

Amber's personal keymap for the Wraith, but with a custom timed function layer keycode. config.h contains defines that you can edit to control various aspects of this function.

How does it work?

We are reading QMK's software timer in matrix_scan_user().

Once the TIME_TOGGLE key is pressed, layer_time_remaining is set equal to LAYER_TIMEOUT, the layer defined in LAYER_SWITCH becomes active, and the LED on the Escape key (pin B0) will light up.

Each time the matrix is scanned, the software timer is read, and the value of layer_time_remaining is decreased by prev_loop_time - the amount of time elapsed since the last matrix scan.

When there are TIMEOUT_WARNINGms left in LAYER_TIMEOUT, the LED will begin to flash at intervals of FLASH_PERIODms.

When there are TIMEOUT_WARNING/TIMEOUT_SCALEms left, the LED will begin to flash at intervals of FLASH_PERIOD/SPEED_SCALEms.

When layer_time_remaining is equal to or less than 0, the layer defined in LAYER_SWITCH is removed from the layer stack.

What are the defaults?

LAYER_TIMEOUT controls how long the layer will stay active for. The default is 10 seconds.

TIMEOUT_WARNING controls how long the warning (LED flash) will occur before the layer becomes inactive. The default is 3 seconds.

FLASH_PERIOD controls how long each LED flash interval is in the warning time. The default flash period is 250ms.

SPEED_SCALE controls how many times faster the LED will flash in the second flash period. The default scale is 2, twice as fast.

TIMEOUT_SCALE controls the length of the second flash period, relative to TIMEOUT_WARNING. The default scale is 4; for 750ms of the secondary flash period.

LAYER_SWITCH is the layer that will be activated by the key. The default is layer 1.