Buttons handling module.
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Buttons handling module.
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.
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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.
#define APP_BUTTON_ACTIVE_HIGH 1 |
Indicates that a button is active high.
#define APP_BUTTON_ACTIVE_LOW 0 |
Indicates that a button is active low.
#define APP_BUTTON_INIT |
( |
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BUTTONS, |
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BUTTON_COUNT, |
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DETECTION_DELAY, |
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USE_SCHEDULER |
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) |
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Value:do \
{ \
(BUTTON_COUNT), \
(DETECTION_DELAY), \
(USE_SCHEDULER) ? app_button_evt_schedule : NULL); \
APP_ERROR_CHECK(ERR_CODE); \
} while (0)
Macro for initializing the Button Handler module.
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
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[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. |
#define APP_BUTTON_PUSH 1 |
Indicates that a button is pushed.
#define APP_BUTTON_RELEASE 0 |
Indicates that a button is released.
#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).
uint32_t app_button_disable |
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void |
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Function for disabling button detection.
- Return values
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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_enable |
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void |
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Function for enabling button detection.
- Return values
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NRF_ERROR_INVALID_PARAM | GPIOTE has to many users. |
NRF_ERROR_INVALID_STATE | Button or GPIOTE not initialized. |
NRF_SUCCESS | Button detection successfully enabled. |
Function for initializing the Buttons.
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).
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app_button_enable() function must be called in order to enable the button detection.
- Parameters
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[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_is_pushed |
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uint8_t |
button_id, |
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bool * |
p_is_pushed |
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) |
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Function for checking if a button is currently being pushed.
- Parameters
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[in] | button_id | Button index (in the app_button_cfg_t array given to app_button_init) to be checked. |
[out] | p_is_pushed | Button state. |
- Return values
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NRF_SUCCESS | State successfully read. |
NRF_ERROR_INVALID_PARAM | Invalid button index. |