There are several Build Options commonly configured in the Makefile.  If you build a custom keymap with your own ~keymap.c~ and ~Makefile~, you will need to determine which of these should be enabled.  

Various of these will cause the firmware to be substantially larger; enabling all of them is probably not possible as the aggregate consumes more memory than is available on the Atmel32U4 used on the Planck.

** BOOTMAGIC_ENABLE

This controls whether or not Virtual DIP switch configuration is supported. (+1000 bytes)

Seldom used (only in one Planck keymap)

** MOUSEKEY_ENABLE
Should some keys simulate mouse activity? (+4700 bytes)

Frequently used in Planck keymaps.

** EXTRAKEY_ENABLE
Controls whether keys for audio and system control are supported. (+450 bytes)

Frequently used in Planck keymaps.

** CONSOLE_ENABLE
Is a debugging console enabled? (+400 bytes)

Infrequently used in Planck keymaps.

** COMMAND_ENABLE
Support commands for debug and configuration

Frequently used

** NKRO_ENABLE
Nkey Rollover - if this doesn't work, see here: [[https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work][TMK FAQ on NKRO]]

Nearly always enabled.

** BACKLIGHT_ENABLE
Enable keyboard backlight functionality

Often enabled

** MIDI_ENABLE

MIDI controls

Seldom enabled.

** AUDIO_ENABLE
Support audio output on port C6

Enabled fairly often

** UNICODE_ENABLE
Enable direct generation of Unicode output

Rarely enabled

** BLUETOOTH_ENABLE

Enable Bluetooth with the Adafruit EZ-Key HID

Only supported on GH60 keyboards with additional Bluetooth HID addon.

** RGBLIGHT_ENABLE

Enable WS2812 RGB underlight.  Do not enable this with audio at the same time.

Rarely enabled.

** API_SYSEX_ENABLE

Enable SYSEX API (+5390 bytes)

This may be useful eventually to enable having events published between keyboard and desktop.

** SLEEP_LED_ENABLE

Breathing sleep LED during USB suspend

It is recommended to not enable SLEEP_LED_ENABLE as it uses the same timer as BACKLIGHT_ENABLE