Description

Energy Management Unit (EMU) Peripheral API.

This module contains functions to control the EMU peripheral of Silicon Labs 32-bit MCUs and SoCs. The EMU handles the different low energy modes in Silicon Labs microcontrollers.

Data Structures
struct	EMU_EM23Init_TypeDef
	EM2 and 3 initialization structure.

struct	EMU_EM4Init_TypeDef
	EM4 initialization structure.

Functions
void	EMU_EM23PresleepHook (void)
	Energy mode 2/3 pre-sleep hook function.

void	EMU_EM23PostsleepHook (void)
	Energy mode 2/3 post-sleep hook function.

void	EMU_EnterEM2 (bool restore)
	Enter energy mode 2 (EM2).

void	EMU_EnterEM3 (bool restore)
	Enter energy mode 3 (EM3).

void	EMU_Save (void)
	Save the CMU HF clock select state, oscillator enable, and voltage scaling (if available) before EMU_EnterEM2() or EMU_EnterEM3() are called with the restore parameter set to false.

void	EMU_Restore (void)
	Restore CMU HF clock select state, oscillator enable, and voltage scaling (if available) after EMU_EnterEM2() or EMU_EnterEM3() are called with the restore parameter set to false.

void	EMU_EnterEM4 (void)
	Enter energy mode 4 (EM4).

void	EMU_EnterEM4H (void)
	Enter energy mode 4 hibernate (EM4H).

void	EMU_EnterEM4S (void)
	Enter energy mode 4 shutoff (EM4S).

void	EMU_MemPwrDown (uint32_t blocks)
	Power down memory block.

void	EMU_RamPowerDown (uint32_t start, uint32_t end)
	Power down RAM memory blocks.

void	EMU_RamPowerUp (void)
	Power up all available RAM memory blocks.

void	EMU_UpdateOscConfig (void)
	Update EMU module with CMU oscillator selection/enable status.

void	EMU_EM23Init (const EMU_EM23Init_TypeDef *em23Init)
	Update the EMU module with Energy Mode 2 and 3 configuration.

void	EMU_EM4Init (const EMU_EM4Init_TypeDef *em4Init)
	Update the EMU module with Energy Mode 4 configuration.

float	EMU_TemperatureGet (void)
	Get temperature in degrees Celcius.

void	EMU_EnterEM1 (void)
	Enter energy mode 1 (EM1).

void	EMU_IntClear (uint32_t flags)
	Clear one or more pending EMU interrupts.

void	EMU_IntDisable (uint32_t flags)
	Disable one or more EMU interrupts.

void	EMU_IntEnable (uint32_t flags)
	Enable one or more EMU interrupts.

uint32_t	EMU_IntGet (void)
	Get pending EMU interrupt flags.

uint32_t	EMU_IntGetEnabled (void)
	Get enabled and pending EMU interrupt flags.

void	EMU_IntSet (uint32_t flags)
	Set one or more pending EMU interrupts.

void	EMU_Lock (void)
	Lock EMU registers in order to protect them against unintended modification.

void	EMU_Unlock (void)
	Unlock the EMU so that writing to locked registers again is possible.

void	EMU_UnlatchPinRetention (void)
	When EM4 pin retention is set to emuPinRetentionLatch, then pins are retained through EM4 entry and wakeup.

bool	EMU_TemperatureReady (void)
	Temperature measurement ready status.

Macros
#define	EMU_TEMPCO_CONST (0.273f)
	As we do not know what energy mode a temperature measurement was taken at, we choose a constant for the TEMPCO calculation that is midway between the EM0/EM1 constant and the EM2/EM3/EM4 constant.

#define	EMU_EM23INIT_DEFAULT
	Default initialization of EM2 and 3 configuration.

#define	EMU_EM4INIT_DEFAULT
	Default initialization of EM4 configuration (Series 1 without VSCALE).

#define	EMU_TEMP_ZERO_C_IN_KELVIN (273.15f)
	Zero degrees Celcius in Kelvin.

Enumerations
enum	EMU_BODMode_TypeDef { emuBODMode_Active , emuBODMode_Inactive }
	BOD threshold setting selector, active or inactive mode.

enum	EMU_EM4State_TypeDef { emuEM4Shutoff = 0, emuEM4Hibernate = 1 }
	EM4 modes.

enum	EMU_EM4PinRetention_TypeDef { emuPinRetentionDisable = EMU_EM4CTRL_EM4IORETMODE_DISABLE, emuPinRetentionEm4Exit = EMU_EM4CTRL_EM4IORETMODE_EM4EXIT, emuPinRetentionLatch = EMU_EM4CTRL_EM4IORETMODE_SWUNLATCH }
	EM4 Pin Retention Type.

enum	EMU_PowerConfig_TypeDef { emuPowerConfig_DcdcToDvdd }
	Power configurations.

Function Documentation

◆ EMU_EM23PresleepHook()

void EMU_EM23PresleepHook ( void )

Energy mode 2/3 pre-sleep hook function.

This function is called by EMU_EnterEM2() and EMU_EnterEM3() functions just prior to execution of the WFI instruction. The function implementation does not perform anything, but it is SL_WEAK so that it can be re- implemented in application code if actions are needed.

Note: The function is primarily meant to be used in systems with EFP circuitry. (EFP = Energy Friendly Pmic (PMIC = Power Management IC)). In such systems there is a need to drive certain signals to EFP pins to notify about energy mode transitions.

◆ EMU_EM23PostsleepHook()

void EMU_EM23PostsleepHook ( void )

Energy mode 2/3 post-sleep hook function.

This function is called by EMU_EnterEM2() and EMU_EnterEM3() functions just after wakeup from the WFI instruction. The function implementation does not perform anything, but it is SL_WEAK so that it can be re- implemented in application code if actions are needed.

Note: The function is primarily meant to be used in systems with EFP circuitry. (EFP = Energy Friendly Pmic (PMIC = Power Management IC)). In such systems there is a need to drive certain signals to EFP pins to notify about energy mode transitions.

◆ EMU_EnterEM2()

void EMU_EnterEM2 ( bool restore )

Enter energy mode 2 (EM2).

When entering EM2, high-frequency clocks are disabled, i.e., HFXO, HFRCO and AUXHFRCO (for AUXHFRCO, see exception note below). When re-entering EM0, HFRCO is re-enabled and the core will be clocked by the configured HFRCO band. This ensures a quick wakeup from EM2.

However, prior to entering EM2, the core may have been using another oscillator than HFRCO. The restore parameter gives the user the option to restore all HF oscillators according to state prior to entering EM2, as well as the clock used to clock the core. This restore procedure is handled by SW. However, since handled by SW, it will not be restored before completing the interrupt function(s) waking up the core!

Note: If restoring core clock to use the HFXO oscillator, which has been disabled during EM2 mode, this function will stall until the oscillator has stabilized. Stalling time can be reduced by adding interrupt support detecting stable oscillator, and an asynchronous switch to the original oscillator. See CMU documentation. Such a feature is however outside the scope of the implementation in this function.; If ERRATA_FIX_EMU_E110_ENABLE is active, the core's SLEEPONEXIT feature can not be used.

: If HFXO is re-enabled by this function, and NOT used to clock the core, this function will not wait for HFXO to stabilize. This must be considered by the application if trying to use features relying on that oscillator upon return.

: If a debugger is attached, the AUXHFRCO will not be disabled if enabled upon entering EM2. It will thus remain enabled when returning to EM0 regardless of the restore parameter.

: If HFXO autostart and select is enabled by using CMU_HFXOAutostartEnable(), the automatic starting and selecting of the core clocks will be done, regardless of the restore parameter, when waking up on the wakeup sources corresponding to the autostart and select setting.

: If voltage scaling is supported, the restore parameter is true and the EM0 voltage scaling level is set higher than the EM2 level, then the EM0 level is also restored.

: On Series 2 Config 2 devices (EFRxG22), this function will also relock the DPLL if the DPLL is used and restore is true.

Note that the hardware will automatically update the HFRCO frequency in the case where voltage scaling is used in EM2/EM3 and not in EM0/EM1. When the restore argument to this function is true then software will restore the original HFRCO frequency after EM2/EM3 wake up. If the restore argument is false then the HFRCO frequency is 19 MHz when coming out of EM2/EM3 and all wait states are at a safe value.

Parameters

[in]


              restore

true - save and restore oscillators, clocks and voltage scaling, see function details.
false - do not save and restore oscillators and clocks, see function details.

: The restore option should only be used if all clock control is done via the CMU API.

◆ EMU_EnterEM3()

void EMU_EnterEM3 ( bool restore )

Enter energy mode 3 (EM3).

When entering EM3, the high-frequency clocks are disabled by hardware, i.e., HFXO, HFRCO, and AUXHFRCO (for AUXHFRCO, see exception note below). In addition, the low-frequency clocks, i.e., LFXO and LFRCO are disabled by software. When re-entering EM0, HFRCO is re-enabled and the core will be clocked by the configured HFRCO band. This ensures a quick wakeup from EM3.

However, prior to entering EM3, the core may have been using an oscillator other than HFRCO. The restore parameter gives the user the option to restore all HF/LF oscillators according to state prior to entering EM3, as well as the clock used to clock the core. This restore procedure is handled by software. However, since it is handled by software, it will not be restored before completing the interrupt function(s) waking up the core!

Note: If restoring core clock to use an oscillator other than HFRCO, this function will stall until the oscillator has stabilized. Stalling time can be reduced by adding interrupt support detecting stable oscillator, and an asynchronous switch to the original oscillator. See CMU documentation. This feature is, however, outside the scope of the implementation in this function.; If ERRATA_FIX_EMU_E110_ENABLE is active, the core's SLEEPONEXIT feature can't be used.

: If HFXO/LFXO/LFRCO are re-enabled by this function, and NOT used to clock the core, this function will not wait for those oscillators to stabilize. This must be considered by the application if trying to use features relying on those oscillators upon return.

: If a debugger is attached, the AUXHFRCO will not be disabled if enabled upon entering EM3. It will, therefore, remain enabled when returning to EM0 regardless of the restore parameter.

: If voltage scaling is supported, the restore parameter is true and the EM0 voltage scaling level is set higher than the EM3 level, then the EM0 level is also restored.

: On Series 2 Config 2 devices (EFRxG22), this function will also relock the DPLL if the DPLL is used and restore is true.

Parameters

[in]


              restore

true - save and restore oscillators, clocks and voltage scaling, see function details.
false - do not save and restore oscillators and clocks, see function details.

: The restore option should only be used if all clock control is done via the CMU API.

◆ EMU_Save()

void EMU_Save ( void )

Save the CMU HF clock select state, oscillator enable, and voltage scaling (if available) before EMU_EnterEM2() or EMU_EnterEM3() are called with the restore parameter set to false.

Calling this function is equivalent to calling EMU_EnterEM2() or EMU_EnterEM3() with the restore parameter set to true, but it allows the state to be saved without going to sleep. The state can be restored manually by calling EMU_Restore() .

◆ EMU_Restore()

void EMU_Restore ( void )

Restore CMU HF clock select state, oscillator enable, and voltage scaling (if available) after EMU_EnterEM2() or EMU_EnterEM3() are called with the restore parameter set to false.

Calling this function is equivalent to calling EMU_EnterEM2() or EMU_EnterEM3() with the restore parameter set to true, but it allows the application to evaluate the wakeup reason before restoring state.

◆ EMU_EnterEM4()

void EMU_EnterEM4 ( void )

Enter energy mode 4 (EM4).

Note: Only a power on reset or external reset pin can wake the device from EM4.

◆ EMU_EnterEM4H()

void EMU_EnterEM4H ( void )

Enter energy mode 4 hibernate (EM4H).

Note: Retention of clocks and GPIO in EM4 can be configured using EMU_EM4Init before calling this function.

◆ EMU_EnterEM4S()

void EMU_EnterEM4S ( void )

Enter energy mode 4 shutoff (EM4S).

Note: Retention of clocks and GPIO in EM4 can be configured using EMU_EM4Init before calling this function.

◆ EMU_MemPwrDown()

void EMU_MemPwrDown ( uint32_t blocks )

Power down memory block.

Parameters

[in] blocks Specifies a logical OR of bits indicating memory blocks to power down. Bit 0 selects block 1, bit 1 selects block 2, and so on. Memory block 0 cannot be disabled. See the reference manual for available memory blocks for a device.

Note: Only a POR reset can power up the specified memory block(s) after power down.

◆ EMU_RamPowerDown()

void EMU_RamPowerDown	(	uint32_t	`start,`
		uint32_t	`end`
	)

Power down RAM memory blocks.

This function will power down all the RAM blocks that are within a given range. The RAM block layout is different between device families, so this function can be used in a generic way to power down a RAM memory region which is known to be unused.

This function will only power down blocks which are completely enclosed by the memory range given by [start, end).

This is an example to power down all RAM blocks except the first one. The first RAM block is special in that it cannot be powered down by the hardware. The size of the first RAM block is device-specific. See the reference manual to find the RAM block sizes.

EMU_RamPowerDown (SRAM_BASE, SRAM_BASE + SRAM_SIZE);

Note: Only a reset can power up the specified memory block(s) after power down on a series 0 device.

Parameters

[in]	`start`	The start address of the RAM region to power down. This address is inclusive.
[in]	`end`	The end address of the RAM region to power down. This address is exclusive. If this parameter is 0, all RAM blocks contained in the region from start to the upper RAM address will be powered down.

◆ EMU_RamPowerUp()

void EMU_RamPowerUp ( void )

Power up all available RAM memory blocks.

This function will power up all the RAM blocks on a device, this means that the RAM blocks are retained in EM2/EM3. Note that this functionality is not supported on Series 0 devices. Only a reset will power up the RAM blocks on a series 0 device.

◆ EMU_UpdateOscConfig()

void EMU_UpdateOscConfig ( void )

Update EMU module with CMU oscillator selection/enable status.

◆ EMU_EM23Init()

void EMU_EM23Init ( const EMU_EM23Init_TypeDef * em23Init )

Update the EMU module with Energy Mode 2 and 3 configuration.

Parameters

[in] em23Init Energy Mode 2 and 3 configuration structure.

◆ EMU_EM4Init()

void EMU_EM4Init ( const EMU_EM4Init_TypeDef * em4Init )

Update the EMU module with Energy Mode 4 configuration.

Parameters

[in] em4Init Energy Mode 4 configuration structure.

◆ EMU_TemperatureGet()

float EMU_TemperatureGet ( void )

Get temperature in degrees Celcius.

Returns: Temperature in degrees Celcius

◆ EMU_EnterEM1()

void EMU_EnterEM1 ( void )

inline

Enter energy mode 1 (EM1).

◆ EMU_IntClear()

void EMU_IntClear ( uint32_t flags )

inline

Clear one or more pending EMU interrupts.

Parameters

[in] flags Pending EMU interrupt sources to clear. Use one or more valid interrupt flags for the EMU module (EMU_IFC_nnn).

◆ EMU_IntDisable()

void EMU_IntDisable ( uint32_t flags )

inline

Disable one or more EMU interrupts.

Parameters

[in] flags EMU interrupt sources to disable. Use one or more valid interrupt flags for the EMU module (EMU_IEN_nnn).

◆ EMU_IntEnable()

void EMU_IntEnable ( uint32_t flags )

inline

Enable one or more EMU interrupts.

Note: Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using EMU_IntClear() prior to enabling the interrupt.

Parameters

[in] flags EMU interrupt sources to enable. Use one or more valid interrupt flags for the EMU module (EMU_IEN_nnn).

◆ EMU_IntGet()

uint32_t EMU_IntGet ( void )

inline

Get pending EMU interrupt flags.

Note: Event bits are not cleared by the use of this function.

Returns: EMU interrupt sources pending. Returns one or more valid interrupt flags for the EMU module (EMU_IF_nnn).

◆ EMU_IntGetEnabled()

uint32_t EMU_IntGetEnabled ( void )

inline

Get enabled and pending EMU interrupt flags.

Useful for handling more interrupt sources in the same interrupt handler.

Note: Interrupt flags are not cleared by the use of this function.

Returns

Pending and enabled EMU interrupt sources Return value is the bitwise AND of

the enabled interrupt sources in EMU_IEN and
the pending interrupt flags EMU_IF.

◆ EMU_IntSet()

void EMU_IntSet ( uint32_t flags )

inline

Set one or more pending EMU interrupts.

Parameters

[in] flags EMU interrupt sources to set to pending. Use one or more valid interrupt flags for the EMU module (EMU_IFS_nnn).

◆ EMU_Lock()

void EMU_Lock ( void )

inline

Lock EMU registers in order to protect them against unintended modification.

Note: If locking EMU registers, they must be unlocked prior to using any EMU API functions modifying EMU registers, excluding interrupt control and regulator control if the architecture has a EMU_PWRCTRL register. An exception to this is the energy mode entering API (EMU_EnterEMn()), which can be used when the EMU registers are locked.

◆ EMU_Unlock()

void EMU_Unlock ( void )

inline

Unlock the EMU so that writing to locked registers again is possible.

◆ EMU_UnlatchPinRetention()

void EMU_UnlatchPinRetention ( void )

inline

When EM4 pin retention is set to emuPinRetentionLatch, then pins are retained through EM4 entry and wakeup.

The pin state is released by calling this function. The feature allows peripherals or GPIO to be re-initialized after EM4 exit (reset), and when initialization is done, this function can release pins and return control to the peripherals or GPIO.

◆ EMU_TemperatureReady()

bool EMU_TemperatureReady ( void )

inline

Temperature measurement ready status.

Returns: True if temperature measurement is ready

Macro Definition Documentation

◆ EMU_TEMPCO_CONST

#define EMU_TEMPCO_CONST (0.273f)

As we do not know what energy mode a temperature measurement was taken at, we choose a constant for the TEMPCO calculation that is midway between the EM0/EM1 constant and the EM2/EM3/EM4 constant.

◆ EMU_EM23INIT_DEFAULT

#define EMU_EM23INIT_DEFAULT

Value:

         {                                                                                                             \
        
         false,
         
          /* Reduced voltage regulator drive strength in EM2/3.*/
         
         \
        
         }

Default initialization of EM2 and 3 configuration.

◆ EMU_EM4INIT_DEFAULT

#define EMU_EM4INIT_DEFAULT

Value:

         {                                                                                    \
        
         false,
         
          /* Retain LFXO configuration upon EM4 entry. */
         
         \
        
         false,
         
          /* Retain LFRCO configuration upon EM4 entry. */
         
         \
        
         false,
         
          /* Retain ULFRCO configuration upon EM4 entry. */
         
         \
        
         emuEM4Shutoff,
         
          /* Use EM4 shutoff state. */
         
         \
        
         emuPinRetentionDisable,
         
          /* Do not retain pins in EM4. */
         
         \
        
         }

Default initialization of EM4 configuration (Series 1 without VSCALE).

◆ EMU_TEMP_ZERO_C_IN_KELVIN

#define EMU_TEMP_ZERO_C_IN_KELVIN (273.15f)

Zero degrees Celcius in Kelvin.

Enumeration Type Documentation

◆ EMU_BODMode_TypeDef

enum EMU_BODMode_TypeDef

BOD threshold setting selector, active or inactive mode.

Enumerator
emuBODMode_Active	Configure BOD threshold for active mode.
emuBODMode_Inactive	Configure BOD threshold for inactive mode.

◆ EMU_EM4State_TypeDef

enum EMU_EM4State_TypeDef

EM4 modes.

Enumerator
emuEM4Shutoff	EM4 Shutoff.
emuEM4Hibernate	EM4 Hibernate.

◆ EMU_EM4PinRetention_TypeDef

enum EMU_EM4PinRetention_TypeDef

EM4 Pin Retention Type.

Enumerator
emuPinRetentionDisable	No Retention: Pads enter reset state when entering EM4.
emuPinRetentionEm4Exit	Retention through EM4: Pads enter reset state when exiting EM4.
emuPinRetentionLatch	Retention through EM4 and wakeup: call EMU_UnlatchPinRetention() to release pins from retention after EM4 wakeup.

◆ EMU_PowerConfig_TypeDef

enum EMU_PowerConfig_TypeDef

Power configurations.

DCDC-to-DVDD is currently the only supported mode.

Enumerator
emuPowerConfig_DcdcToDvdd	DCDC is connected to DVDD.

EMU - Energy Management Unit

Description

Data Structures

Functions

Macros

Enumerations

Function Documentation

◆ EMU_EM23PresleepHook()

◆ EMU_EM23PostsleepHook()

◆ EMU_EnterEM2()

◆ EMU_EnterEM3()

◆ EMU_Save()

◆ EMU_Restore()

◆ EMU_EnterEM4()

◆ EMU_EnterEM4H()

◆ EMU_EnterEM4S()

◆ EMU_MemPwrDown()

◆ EMU_RamPowerDown()

◆ EMU_RamPowerUp()

◆ EMU_UpdateOscConfig()

◆ EMU_EM23Init()

◆ EMU_EM4Init()

◆ EMU_TemperatureGet()

◆ EMU_EnterEM1()

◆ EMU_IntClear()

◆ EMU_IntDisable()

◆ EMU_IntEnable()

◆ EMU_IntGet()

◆ EMU_IntGetEnabled()

◆ EMU_IntSet()

◆ EMU_Lock()

◆ EMU_Unlock()

◆ EMU_UnlatchPinRetention()

◆ EMU_TemperatureReady()

Macro Definition Documentation

◆ EMU_TEMPCO_CONST

◆ EMU_EM23INIT_DEFAULT

◆ EMU_EM4INIT_DEFAULT

◆ EMU_TEMP_ZERO_C_IN_KELVIN

Enumeration Type Documentation

◆ EMU_BODMode_TypeDef

◆ EMU_EM4State_TypeDef

◆ EMU_EM4PinRetention_TypeDef

◆ EMU_PowerConfig_TypeDef