Button

Files
file	button.h
	The button module enables event-driven and polling access to the buttons of the SPiCboard.
Typedefs
typedef void(*	buttoncallback_t )(BUTTON, BUTTONEVENT)
	Type for button event callback functions.
Enumerations
enum	BUTTON { BUTTON0 = 4, BUTTON1 = 8 }
	Identifiers for all available buttons. More...
enum	BUTTONEVENT { BTNPRESSED = 1, BTNRELEASED = 2 }
	Events for buttons. More...
Functions
int8_t	sb_button_registerListener (BUTTON btn, BUTTONEVENT eve, buttoncallback_t callback)
	Register a callback function for a button event.
int8_t	sb_button_unregisterListener (BUTTON btn, BUTTONEVENT eve, buttoncallback_t callback)
	Unregister a callback function for a button event.
BUTTONEVENT	sb_button_getState (BUTTON btn)
	Query the current state of a button.

---

Typedef Documentation

typedef void(* buttoncallback_t)(BUTTON, BUTTONEVENT)

Type for button event callback functions.

A button callback function is called on the interrupt level whenever an event at a button occurs that the function was registered for. The callback function is passed the button id and the type of event that occurred. This way, the same callback function can be registered for different buttons and events.

---

Enumeration Type Documentation

enum BUTTON

Identifiers for all available buttons.

Enumerator:

BUTTON0	Button 0
BUTTON1	Button 1

enum BUTTONEVENT

Events for buttons.

Pressed and released events for buttons.

Enumerator:

BTNPRESSED	Button was pressed
BTNRELEASED	Button was released

---

Function Documentation

BUTTONEVENT sb_button_getState

(

BUTTON

btn

)

Query the current state of a button.

Parameters:

btn

id of the button

Returns:

The buttons current state (pressed or released) as a BUTTONEVENT

int8_t sb_button_registerListener	(	BUTTON	btn,
		BUTTONEVENT	eve,
		buttoncallback_t	callback
	)

Register a callback function for a button event.

Parameters:

	btn	the id of the button
	eve	the type of event that the callback function should be invoked for. event types can be bitwise or'd to register a callback for both pressed and released events.
	callback	pointer to the callback function. This function is called from the interrupt handler.

Return values:

	0	success,
	!0	error

See also:

sb_button_unregisterListener

buttoncallback_t

int8_t sb_button_unregisterListener	(	BUTTON	btn,
		BUTTONEVENT	eve,
		buttoncallback_t	callback
	)

Unregister a callback function for a button event.

Parameters:

	btn	the id of the button
	eve	the type of event that the callback function should be invoked for. event types can be bitwise or'd to register a callback for both pressed and released events.
	callback	pointer to the callback function

Returns:

0 on success, negative value on error

Return values:

	0	success
	-1	the callback function was not registered with the given button/event combination

See also:

sb_button_registerListener