Button#

Sample API functions for using push-buttons.

See sl_si91x_button.c for source code.

Introduction#

The SI91x button driver is a platform-level software module responsible for managing the initialization and reading buttons. It offers a comprehensive set of functions for button operations, including initialization, state monitoring, and callback handling for state changes. The driver supports flexible interrupt configurations, enabling detection based on button state, edge transitions, or both. All button functions are called through the generic driver, which internally triggers specific functions to the respective button.

Configuration#

All button instances are configured with an sl_button_t struct. This struct is automatically generated after a button is set up using Simplicity Studio's wizard.

For more information on configuring available parameters refer to the respective peripheral example readme document and refer here https://docs.silabs.com/wiseconnect/latest/wiseconnect-api-reference-guide-si91x-peripherals/disable-uc-config.

Usage#

Once the button structures are defined, the button functions can be invoked by passing an instance of sl_button_t, which will be redirected to call the type-specific version of that function. The common functions include the following:

sl_button_init is called automatically when the application is run.

The button driver can be used with interrupt mode, with or without debounce. sl_si91x_button_pin_state can be implemented by the application if required. This function is used to determine the current state of the button. sl_si91x_button_state_toggle can be implemented by the application. This function toggles the "soft" state so that it gives the interrupts and their callbacks. sl_si91x_button_isr is a callback function that is called when the button state changes. This function can be implemented in the application to specify what the user wants to do when the button state changes.

Modules#

sl_button_t

Macros#

A set of numerical macros for use with the button APIs.

#define

HIGH_LEVEL_INTERRUPT 1U

Interrupt on low/pressed button state can be configured.

#define

LOW_LEVEL_INTERRUPT 2U

Interrupt on low/pressed button state can be configured.

#define

HIGH_LEVEL_AND_LOW_LEVEL_INTERRUPT 3U

Interrupt on low/pressed and high/released button state can be configured.

#define

RISE_EDGE_INTERRUPT 4U

Interrupt on rising edge of the button press.

#define

FALL_EDGE_INTERRUPT 8U

Interrupt on falling edge of the button press.

#define

RISE_EDGE_AND_FALL_EDGE_INTERRUPT 12U

Interrupt on rising edge and falling edge of the button press.

#define

BUTTON_PRESSED 1

Button state is pressed.

#define

BUTTON_RELEASED 0

Button state is released.

#define

BUTTON_STATE_INVALID -1

Button state is invalid.

Functions#

void

sl_si91x_button_init(const sl_button_t *handle)

Initializes the button, a process automatically triggered upon the creation of a button instance, sets the mode of operation, and configures interrupts based on the selected mode.

int8_t

sl_si91x_button_state_get(uint8_t pin)

Returns the current state (pressed or released) of a button.

int8_t

sl_si91x_button_pin_state(uint8_t pin)

Returns the current state (pressed or released) of the pin associated with a button.

void

sl_si91x_button_pin_isr(uint8_t pin, uint8_t state)

A callback called in interrupt context whenever a button changes its state.

void

sl_si91x_button_state_toggle(uint8_t pin)

Toggles the value of a local variable associated with the state of button.

void

sl_si91x_button_state_set(uint8_t pin, int8_t state)

Sets the state (pressed or released) of the pin associated with a button.

void

sl_si91x_button_isr(uint8_t pin, int8_t state)

A callback that user can modify for the application.

Macros Documentation#

Function Documentation#

sl_si91x_button_init#

void sl_si91x_button_init (const sl_button_t * handle)

Initializes the button, a process automatically triggered upon the creation of a button instance, sets the mode of operation, and configures interrupts based on the selected mode.

Parameters

Type	Direction	Argument Name	Description
const sl_button_t *	[in]	handle	The pointer to button structure that has the specific button information.

Returns

none

sl_si91x_button_state_get#

int8_t sl_si91x_button_state_get (uint8_t pin)

Returns the current state (pressed or released) of a button.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin being queried, either BUTTON0 pin or BUTTON1 pin as defined.

Note

This function is correlated with sl_si91x_button_isr() and so returns the shadow state rather than reading the actual state of the pin.

Returns

BUTTON_PRESSED if the button is pressed or BUTTON_RELEASED if the button is not pressed.

sl_si91x_button_pin_state#

int8_t sl_si91x_button_pin_state (uint8_t pin)

Returns the current state (pressed or released) of the pin associated with a button.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin being queried, either BUTTON0 pin or BUTTON1 pin as defined.

This reads the actual state of the pin and can be used on startup to determine the initial position of the buttons.

Returns

BUTTON_PRESSED if the button is pressed or BUTTON_RELEASED if the button is not pressed.

sl_si91x_button_pin_isr#

void sl_si91x_button_pin_isr (uint8_t pin, uint8_t state)

A callback called in interrupt context whenever a button changes its state.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin which has changed state, either BUTTON0 pin or BUTTON1 pin as defined.
uint8_t	[out]	state	The new state of the button referenced by the button parameter, either BUTTON_PRESSED if the button has been pressed or BUTTON_RELEASED if the button has been released.

Note

Must be implemented by the application. This function should contain the functionality to be executed in response to changes of state in each of the buttons, or callbacks to the appropriate functionality.

Returns

none

sl_si91x_button_state_toggle#

void sl_si91x_button_state_toggle (uint8_t pin)

Toggles the value of a local variable associated with the state of button.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin which has changed state, either BUTTON0 pin or BUTTON1 pin as defined.

Note

Must be implemented by the application. This function should contain the functionality to be executed in response to changes of state in each of the buttons, or callbacks to the appropriate functionality.

Returns

none

sl_si91x_button_state_set#

void sl_si91x_button_state_set (uint8_t pin, int8_t state)

Sets the state (pressed or released) of the pin associated with a button.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin which has changed state, either BUTTON0 pin or BUTTON1 pin as defined.
int8_t	[in]	state	The state of the button to be set, either BUTTON_PRESSED if the button state is pressed or BUTTON_RELEASED if the button state is released.

Note

Must be implemented by the application. This function should contain the functionality to be executed in response to changes of state in each of the buttons, or callbacks to the appropriate functionality.

Returns

none

sl_si91x_button_isr#

void sl_si91x_button_isr (uint8_t pin, int8_t state)

A callback that user can modify for the application.

Parameters

Type	Direction	Argument Name	Description
uint8_t	[in]	pin	The button pin which has changed state, either BUTTON0 pin or BUTTON1 pin as defined.
int8_t	[in]	state	The new state of the button referenced by the button parameter, either BUTTON_PRESSED if the button is pressed or BUTTON_RELEASED if the button is released.

Note

Must be implemented by the application. This function should contain the functionality to be executed in response to changes of state in each of the buttons, or callbacks to the appropriate functionality.

Returns

none