Button Handler

Buttons handling module. More...

Macros
#define	APP_BUTTON_SCHED_EVT_SIZE   sizeof(app_button_event_t)
#define	APP_BUTTON_INIT(BUTTONS, BUTTON_COUNT, DETECTION_DELAY, USE_SCHEDULER)
	Macro for initializing the Button Handler module. More...

Typedefs
typedef void(*	app_button_handler_t )(uint8_t pin_no)
	Button event handler type.
typedef uint32_t(*	app_button_evt_schedule_func_t )(app_button_handler_t button_handler, uint8_t pin_no)
	Type of function for passing events from the Button Handler module to the scheduler.

Functions
uint32_t	app_button_init (app_button_cfg_t *p_buttons, uint8_t button_count, uint32_t detection_delay, app_button_evt_schedule_func_t evt_schedule_func)
	Function for initializing the Buttons. More...
uint32_t	app_button_enable (void)
	Function for enabling button detection. More...
uint32_t	app_button_disable (void)
	Function for disabling button detection. More...
uint32_t	app_button_is_pushed (uint8_t pin_no, bool *p_is_pushed)
	Function for checking if a button is currently being pushed. More...

Data Structures
struct	app_button_cfg_t
	Button configuration structure. More...

Detailed Description

The button handler uses the GPIOTE Handler to detect that a button has been pushed. To handle debouncing, it will start a timer in the GPIOTE event handler. The button will only be reported as pushed if the corresponding pin is still active when the timer expires. If there is a new GPIOTE event while the timer is running, the timer is restarted. Use the USE_SCHEDULER parameter of the APP_BUTTON_INIT() macro to select if the Scheduler is to be used or not.

Note

The app_button module uses the app_timer module. The user must ensure that the queue in app_timer is large enough to hold the app_timer_stop() / app_timer_start() operations which will be executed on each event from GPIOTE module (2 operations), as well as other app_timer operations queued simultaneously in the application.

Even if the scheduler is not used, app_button.h will include app_scheduler.h, so when compiling, app_scheduler.h must be available in one of the compiler include paths.

Macro Definition Documentation

#define APP_BUTTON_SCHED_EVT_SIZE   sizeof(app_button_event_t)

Size of button events being passed through the scheduler (is to be used for computing the maximum size of scheduler events).

#define APP_BUTTON_INIT	(		BUTTONS,
			BUTTON_COUNT,
			DETECTION_DELAY,
			USE_SCHEDULER
	)

Value:

do                                                                                             \
    {                                                                                              \
        uint32_t ERR_CODE = app_button_init((BUTTONS),                                             \
                                            (BUTTON_COUNT),                                        \
                                            (DETECTION_DELAY),                                     \
                                            (USE_SCHEDULER) ? app_button_evt_schedule : NULL);     \
        APP_ERROR_CHECK(ERR_CODE);                                                                 \
    } while (0)

It will initialize the specified pins as buttons, and configure the Button Handler module as a GPIOTE user (but it will not enable button detection). It will also connect the Button Handler module to the scheduler (if specified).

Parameters

[in]	BUTTONS	Array of buttons to be used (type app_button_cfg_t, must be static!).
[in]	BUTTON_COUNT	Number of buttons.
[in]	DETECTION_DELAY	Delay from a GPIOTE event until a button is reported as pushed.
[in]	USE_SCHEDULER	TRUE if the application is using the event scheduler, FALSE otherwise.

Function Documentation

uint32_t app_button_init	(	app_button_cfg_t *	p_buttons,
		uint8_t	button_count,
		uint32_t	detection_delay,
		app_button_evt_schedule_func_t	evt_schedule_func
	)

This function will initialize the specified pins as buttons, and configure the Button Handler module as a GPIOTE user (but it will not enable button detection).

Note

Normally initialization should be done using the APP_BUTTON_INIT() macro, as that will take care of connecting the Buttons module to the scheduler (if specified).

app_button_enable() function must be called in order to enable the button detection.

Parameters

[in]	p_buttons	Array of buttons to be used (NOTE: Must be static!).
[in]	button_count	Number of buttons.
[in]	detection_delay	Delay from a GPIOTE event until a button is reported as pushed.
[in]	evt_schedule_func	Function for passing button events to the scheduler. Point to app_button_evt_schedule() to connect to the scheduler. Set to NULL to make the Buttons module call the event handler directly from the delayed button push detection timeout handler.

Returns

NRF_SUCCESS on success, otherwise an error code.

uint32_t app_button_enable

(

void

)

Return values

NRF_ERROR_INVALID_PARAM	GPIOTE has to many users.
NRF_ERROR_INVALID_STATE	Button or GPIOTE not initialized.
NRF_SUCCESS	Button detection successfully enabled.

uint32_t app_button_disable

(

void

)

Return values

NRF_ERROR_INVALID_PARAM	GPIOTE has to many users.
NRF_ERROR_INVALID_STATE	Button or GPIOTE not initialized.
NRF_SUCCESS	Button detection successfully enabled.

uint32_t app_button_is_pushed	(	uint8_t	pin_no,
		bool *	p_is_pushed
	)

Parameters

[in]	pin_no	Button pin to be checked.
[out]	p_is_pushed	Button state.

Return values

NRF_SUCCESS	State successfully read.
NRF_ERROR_INVALID_PARAM	Invalid pin_no.