Power Manager API Reference#

This section provides an overview of the callback and notification mechanisms available in the Power Manager Service for Silicon Labs SiWx917 devices. These APIs enable applications to respond to power-state transitions and wakeup events, allowing for efficient and responsive power management.

For detailed API documentation, see the official reference: API Guide: Power Manager Service for Silicon Labs SiWx917

Callback and Notification APIs#

The Power Manager Service supports two primary types of callbacks:

  • Transition callbacks: Triggered during power-state changes.

  • Wakeup source callbacks: Triggered when the system wakes from sleep due to specific wakeup sources.

These callbacks let applications monitor and respond to system power events in real time.

Transition Callbacks for Power-State Changes#

Transition callbacks notify the application when the system enters or exits specific power states, letting developers perform tasks such as saving system state, reconfiguring peripherals, or logging transitions.

Overview#

The Power Manager exposes a set of transition events. Applications can register handlers for these events by using the subscription API. These handlers are invoked automatically during power-state transitions.

Callback Function Definition#

typedef void (*sl_power_manager_ps_transition_event_handle_t)(
    sl_power_state_t from,
    sl_power_state_t to
);

  • sl_power_state_t: Represents the system power state.

  • from: The power state the system is transitioning from.

  • to: The power state the system is transitioning to.

Example Callback Implementation#

void my_power_transition_handler(sl_power_state_t from, sl_power_state_t to) {
    if (to == SL_SI91X_POWER_MANAGER_PS2) {
        // Transitioning to PS2: eg: Configure ULP peripherals
    } else if (from == SL_SI91X_POWER_MANAGER_PS2) {
        // Transitioning from PS2: eg: Configure HP peripherals
    }
}

Available Transition Events#

Entering power states:

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_ENTERING_PS4

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_ENTERING_PS3

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_ENTERING_PS2

Leaving power states:

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_PS4

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_PS3

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_PS2

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_PS1

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_SLEEP

  • SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_STANDBY

Registering a Transition Callback#

Use the following API to subscribe to transition events:

sl_status_t sl_si91x_power_manager_subscribe_ps_transition_event(
    sl_power_manager_ps_transition_event_handle_t *event_handle,
    const sl_power_manager_ps_transition_event_info_t *event_info);

Example:

void setup_transition_callback(void)
{
    sl_power_manager_ps_transition_event_handle_t event_handle;
    sl_power_manager_ps_transition_event_info_t event_info = {
        .event_mask = SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_ENTERING_PS2 |
                      SL_SI91X_POWER_MANAGER_EVENT_TRANSITION_LEAVING_PS2,
        .on_event = my_power_transition_handler
    };

    sl_si91x_power_manager_subscribe_ps_transition_event(&event_handle, &event_info);
}

Unsubscribing from Transition Callbacks#

void cleanup_transition_callbacks(sl_power_manager_ps_transition_event_handle_t *handle)
{
    sl_si91x_power_manager_unsubscribe_ps_transition_event(handle);
}

Wakeup Source Callbacks#

Wakeup source callbacks are triggered when the system wakes from sleep due to a configured source, such as GPIO (general-purpose input/output), calendar alarms, or timers. These callbacks are automatically registered when the wakeup source is configured by using the Universal Configurator (UC).

Overview#

Each wakeup source has a corresponding callback function. These functions let the application resume operations, process input, or handle time-based events after waking from sleep.

Example Callback Implementations#

// GPIO wakeup callback
void gpio_uulp_pin_interrupt_callback(void)
{
    // Handle GPIO-triggered wakeup
    // Check GPIO pin states, process input
}

// Calendar alarm wakeup callback
void calendar_alarm_callback_function(void)
{
    // Handle calendar alarm-triggered wakeup
    // Resume scheduled tasks, process time-based events
}

// Calendar second callback
void calendar_second_callback_function(void)
{
    // Handle calendar second tick
    // Update time displays, time-based operations
}

// Deep Sleep Timer callback
void dst_callback_function(void)
{
    // Handle Deep Sleep Timer wakeup
    // Resume scheduled tasks, update time-based operations
}

Integration#

To use these callbacks:

  1. Define the callback function in your application.

  2. Configure the wakeup source by using UC.

  3. The Power Manager automatically registers the callback.

Example:

void dst_callback_function(void)
{
    // Perform application-specific processing
    // Resume scheduled tasks, update time-based operations
}

Ensure that all callback functions follow the correct signature and are defined before configuring the wakeup source.