Power Manager API Reference#

API Overview#

The Power Manager provides the following comprehensive API categories for power management:


API Category	Description
Core Sleep Control	Essential functions for power manager initialization, sleep entry, and energy mode requirements
Ultra-Low-Power (EM4)	Specialized APIs for EM4 deep sleep mode with system reset and pin retention capabilities
Event Notification	Subscription system for power transition events enabling coordinated power state management
Execution Modes (Series 3)	Performance scaling APIs for dynamic clock frequency management on Series 3 devices
Schedule Wake-up Tuning	Advanced timing optimization functions for fine-tuning power transition behavior
Advanced Power Control	Specialized functions for voltage scaling, wake-up analysis, and runtime clock configuration updates
Sleep Decision Callbacks	Application hooks for controlling sleep behavior in bare-metal applications
Debug and Diagnostics	Development and troubleshooting tools for analyzing power management behavior

The following table lists all the functions in each API category for quick reference by function names:


Category	Functions
Core Sleep Control	`sl_power_manager_init()`, `sl_power_manager_sleep()`, `sl_power_manager_add_em_requirement()`, `sl_power_manager_remove_em_requirement()`
Ultra-Low-Power (EM4)	`sl_power_manager_enter_em4()`, `sl_power_manager_em4_unlatch_pin_retention()`, `sl_power_manager_em4_presleep_hook()`
Event Notification	`sl_power_manager_subscribe_em_transition_event()`, `sl_power_manager_unsubscribe_em_transition_event()`
Execution Modes (Series 3)	`sl_power_manager_add_performance_mode_requirement()`, `sl_power_manager_remove_performance_mode_requirement()`
Schedule Wake-up Tuning	`sl_power_manager_schedule_wakeup_get_restore_overhead_tick()`, `sl_power_manager_schedule_wakeup_set_restore_overhead_tick()`, `sl_power_manager_schedule_wakeup_get_minimum_offtime_tick()`, `sl_power_manager_schedule_wakeup_set_minimum_offtime_tick()`
Advanced Power Control	`sl_power_manager_em23_voltage_scaling_enable_fast_wakeup()`, `sl_power_manager_is_latest_wakeup_internal()`, `slx_power_manager_update_clock_info()`
Sleep Decision Callbacks	`sl_power_manager_is_ok_to_sleep()`, `sl_power_manager_sleep_on_isr_exit()`
Debug and Diagnostics	`sl_power_manager_debug_print_em_requirements()`

This section focuses on essential APIs for typical power management use cases. For advanced APIs and complete reference, see the full API documentation.

Core Sleep Control#

void sl_power_manager_sleep(void);
void sl_power_manager_add_em_requirement(sl_power_manager_em_t em);
void sl_power_manager_remove_em_requirement(sl_power_manager_em_t em);

sl_power_manager_sleep()

Purpose: Enters lowest allowable energy mode automatically
Context: Main thread only (not from ISR)
Behavior: Selects EM1 or EM2/3 based on active requirements
Typical Usage: Not necessary to call manually - automatically called by bare-metal template main loop and RTOS idle task

sl_power_manager_add_em_requirement(em) / sl_power_manager_remove_em_requirement(em)

Purpose: Add/remove energy mode requirements to prevent sleep deeper than specified mode
Parameters: SL_POWER_MANAGER_EM1 (only accepted value)
Context: Safe from ISR
Important: Only remove requirements previously added by your module
ISR Timing: When called from ISR during EM2 sleep, adding EM1 requirements will block until system restore is finished
Usage Example: See Scenario 1: Asynchronous Sensor Reading for a practical demonstration of requirement management and sleep control

Ultra-Low-Power (EM4) APIs#

__NO_RETURN void sl_power_manager_enter_em4(void);

sl_power_manager_enter_em4()

Purpose: Enters deepest sleep mode
Return: Never returns - device resets on wake-up
Wake Sources: External pins, RTC, reset
Usage Example: See Scenario 2: Ultra-Low Power EM4 Sleep for a complete implementation example

Event Notification APIs#

void sl_power_manager_subscribe_em_transition_event(
    sl_power_manager_em_transition_event_handle_t *event_handle,
    const sl_power_manager_em_transition_event_info_t *event_info);
void sl_power_manager_unsubscribe_em_transition_event(
    sl_power_manager_em_transition_event_handle_t *event_handle);

sl_power_manager_subscribe_em_transition_event() / sl_power_manager_unsubscribe_em_transition_event()

Purpose: Subscribe to/unsubscribe from energy mode transition event notifications - essential for modules that need to prepare for or respond to power state changes
Parameters:
- event_handle: Pointer to handle structure that will be populated for later unsubscription
- event_info: Pointer to structure containing callback function and configuration
Context: Safe to call from main thread during initialization/cleanup
Usage Example: See Using Event Notifications for complete callback implementation and context management

Execution Mode APIs (Series 3 Only)#

void sl_power_manager_add_performance_mode_requirement(void);
void sl_power_manager_remove_performance_mode_requirement(void);

sl_power_manager_add_performance_mode_requirement() / sl_power_manager_remove_performance_mode_requirement()

Purpose: Add/remove performance mode requirements to switch between Standard and Performance execution modes
Device Support: Series 3 (SIXG301) only
Power Impact: Higher power consumption in Performance mode but faster processing
Series 2 Compatibility: On Series 2, these APIs are no-ops
Usage Example: See Execution Modes (Series 3 Only) for dynamic performance scaling implementation