Buttons module

The buttons module is responsible for generating events related to key presses. The source of events are changes to GPIO pins.

Module events

Source Module	Input Event	This Module	Output Event	Sink Module
Power manager module	power_down_event	buttons
Source modules for module_state_event	module_state_event
Buttons module	wake_up_event
HID forward module
Motion module
Power manager module
Wheel module
			button_event	Function key module
				Motion module
				Button simulator module
				Click detector module
				Passkey module
				HID state module
			module_state_event	Sink modules for module_state_event
			wake_up_event	Sink modules for wake_up_event

Note

See the Overview: Firmware architecture for more information about the event-based communication in the nRF Desktop application and about how to read this table.

Implementation details

nRF Desktop uses the buttons module from Common Application Framework (CAF). See the CAF button module page for implementation details.

Key ID

If CONFIG_DESKTOP_FN_KEYS_ENABLE is enabled, the button_event.key_id additionally encodes if a button related to button_event is a function key. See the nRF Desktop function key module page for implementation details.