Overview

The MCUXpresso SDK provides a peripheral driver for the Smart Power Switch (VBAT) block of MCUXpresso SDK devices. The VBAT includes the following features:

Oscillator for 32.768 kHz crystal (OSC32K);
- The OSC32K is disabled by default on VBAT PORT.
- When enabled, it takes the oscillator start-up time before the OSC_RDY flag is set and the clock is output to other modules.
Internal 16 kHz free running oscillator (FRO16k);
- The FRO16K is enabled by default on VBAT POR.
- It can be disabled by software.
Backup retention SRAM regulator(SRAM LDO).
- The SRAM LDO is a retention regulator used to retain VBAT retention SRAM in low power modes, including when VBAT is the only available supply.
- Before entering a low power mode where the retention SRAM is powered by VBAT supply, software must enable the bandgap and LDO.
- The refresh mode must also be enabled for lowest power consumption.

Based on VBAT's features the VBAT driver are divided into 6 function groups.

FRO16K Control Interfaces

Functions in this group can be used to configure internal 16kHz free running oscillator.

To enable and lock the FRO16K:

Invoke VBAT_EnableFRO16k(VBAT0, true) to enable FRO16K;
Invoke VBAT_LockFRO16kSettings(VBAT0) to lock FRO16K settings;
Invoke VBAT_UngateFRO16k(VBAT0, kVBAT_EnableClockToVddBat | kVBAT_EnableClockToVddSys) to ungate clock to VDD_BAT power domain and VDD_SYS power domain.

OSC32K Control Interfaces

Functions in this group can be used to configure internal 32k crystal oscillator.

To configure and lock OSC32kHz for lowest power operation(Switched mode):

Invoke VBAT_SetCrystalOsc32kModeAndLoadCapacitance(VBAT0, kVBAT_Osc32kEnabledToLowPowerSwitchedMode, kVBAT_Osc32kCrystalLoadCap0pF, kVBAT_Osc32kCrystalLoadCap0pF) to set OSC32k as low power switched mode.
Invoke VBAT_EnableCrystalOsc32k(VBAT0, true) to enable OSC32kHz.
Invoke VBAT_LookOsc32kSettings(VBAT0) to lock OSC32k settings.
Invoke VBAT_UngateOsc32k(VBAT0, kVBAT_EnableClockToVddBat | kVBAT_EnableClockToVddSys) to ungate clock to VDD_BAT power domain and VDD_SYS power domain.

RAM_LDO Control Interfaces

Functions in this group can be used to control internal bandgap and RAM_LDO.

To enable and lock the LDO and bandgap:

Check if FRO16k is enabled by invoking VBAT_CheckFRO16kEnabled(VBAT0).
Invoke VBAT_EnableBandgap(VBAT0, true) to enable bandgap.
Invoke VBAT_EnableBandgapRefreshMode(VBAT0, true) to enable bandgap low power refresh mode.
Invoke VBAT_EnableBackupSRAMRegulator(VBAT0, true) to enable backup SRAM regulator.
Invoke VBAT_LockRamLdoSettings(VBAT0) to lock LDO settings.

Bandgap Timer Control Interfaces

Functions in this group can be used to control internal software bandgap timers. Please note that bandgap timers are available when the bandgap is enabled and are clocked by the FRO16k.

Status, Interrupt, Wakeup Control Interfaces

VBAT_GetStatusFlags() and VBAT_ClearStatusFlags() function in this group can be used to get and clear status flags. VBAT_EnableInterrupts() and VBAT_DisableInterrupts() function in this group can be used to enable/disable interrupt. VBAT_EnableWakeup() and VBAT_DisableWakeup() function in this group can be used to enable/disable wakeup features.

Switch Control Interfaces

Functions in this group can be used to switch power supply of VBAT modules.

Data Structures
struct	vbat_fro16k_config_t
	The structure of internal 16kHz free running oscillator attributes. More...

Enumerations
enum	{ kStatus_VBAT_Fro16kNotEnabled = MAKE_STATUS(kStatusGroup_VBAT, 0), kStatus_VBAT_BandgapNotEnabled = MAKE_STATUS(kStatusGroup_VBAT, 1), kStatus_VBAT_WrongCapacitanceValue = MAKE_STATUS(kStatusGroup_VBAT, 2), kStatus_VBAT_ClockMonitorLocked = MAKE_STATUS(kStatusGroup_VBAT, 3), kStatus_VBAT_OSC32KNotReady = MAKE_STATUS(kStatusGroup_VBAT, 4), kStatus_VBAT_LDONotReady = MAKE_STATUS(kStatusGroup_VBAT, 5), kStatus_VBAT_TamperLocked = MAKE_STATUS(kStatusGroup_VBAT, 6) }
	The enumeration of VBAT module status. More...

enum	_vbat_clock_enable { kVBAT_EnableClockToDomain0 = 1U << 0U, kVBAT_EnableClockToDomain1 = 1U << 1U, kVBAT_EnableClockToDomain2 = 1U << 2U, kVBAT_EnableClockToDomain3 = 1U << 3U }
	The enumeration of connections for OSC32K/FRO32K output clock to other modules. More...

enum	vbat_bandgap_refresh_period_t { kVBAT_BandgapRefresh7P8125ms = 0U, kVBAT_BandgapRefresh15P625ms = 1U, kVBAT_BandgapRefresh31P25ms = 2U, kVBAT_BandgapRefresh62P5ms = 3U }
	The enumeration of bandgap refresh period. More...

Driver version
#define	FSL_VBAT_DRIVER_VERSION (MAKE_VERSION(2, 3, 1))
	VBAT driver version 2.3.1. More...

FRO16K Control Interfaces
void	VBAT_ConfigFRO16k (VBAT_Type base, const vbat_fro16k_config_t config)
	Configure internal 16kHz free running oscillator, including enabel FRO16k, gate FRO16k output. More...

static void	VBAT_EnableFRO16k (VBAT_Type *base, bool enable)
	Enable/disable internal 16kHz free running oscillator. More...

static bool	VBAT_CheckFRO16kEnabled (VBAT_Type *base)
	Check if internal 16kHz free running oscillator is enabled. More...

static void	VBAT_UngateFRO16k (VBAT_Type *base, uint8_t connectionsMask)
	Enable FRO16kHz output clock to selected modules. More...

static void	VBAT_GateFRO16k (VBAT_Type *base, uint8_t connectionsMask)
	Disable FRO16kHz output clock to selected modules. More...

static void	VBAT_LockFRO16kSettings (VBAT_Type *base)
	Lock settings of internal 16kHz free running oscillator, please note that if locked 16kHz FRO's settings can not be updated until the next POR. More...

static bool	VBAT_CheckFRO16kSettingsLocked (VBAT_Type *base)
	Check if FRO16K settings are locked. More...

Data Structure Documentation

struct vbat_fro16k_config_t

Data Fields
bool	enableFRO16k
	Enable/disable internal 16kHz free running oscillator. More...

uint8_t	enabledConnectionsMask
	The mask of connected modules to enable FRO16k clock output. More...

Field Documentation

bool vbat_fro16k_config_t::enableFRO16k

uint8_t vbat_fro16k_config_t::enabledConnectionsMask

Macro Definition Documentation

#define FSL_VBAT_DRIVER_VERSION (MAKE_VERSION(2, 3, 1))

Enumeration Type Documentation

anonymous enum

Enumerator
kStatus_VBAT_Fro16kNotEnabled	Internal 16kHz free running oscillator not enabled.
kStatus_VBAT_BandgapNotEnabled	Bandgap not enabled.
kStatus_VBAT_WrongCapacitanceValue	Wrong capacitance for selected oscillator mode.
kStatus_VBAT_ClockMonitorLocked	Clock monitor locked.
kStatus_VBAT_OSC32KNotReady	OSC32K not ready.
kStatus_VBAT_LDONotReady	LDO not ready.
kStatus_VBAT_TamperLocked	Tamper locked.

enum _vbat_clock_enable

Enumerator
kVBAT_EnableClockToDomain0	Enable clock to power domain0.
kVBAT_EnableClockToDomain1	Enable clock to power domain1.
kVBAT_EnableClockToDomain2	Enable clock to power domain2.
kVBAT_EnableClockToDomain3	Enable clock to power domain3.

enum vbat_bandgap_refresh_period_t

Enumerator
kVBAT_BandgapRefresh7P8125ms	Bandgap refresh every 7.8125ms.
kVBAT_BandgapRefresh15P625ms	Bandgap refresh every 15.625ms.
kVBAT_BandgapRefresh31P25ms	Bandgap refresh every 31.25ms.
kVBAT_BandgapRefresh62P5ms	Bandgap refresh every 62.5ms.

Function Documentation

void VBAT_ConfigFRO16k	(	VBAT_Type *	base,
		const vbat_fro16k_config_t *	config
	)

Parameters

base	VBAT peripheral base address.
config	Pointer to vbat_fro16k_config_t structure.

static void VBAT_EnableFRO16k	(	VBAT_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	VBAT peripheral base address.
enable	Used to enable/disable 16kHz FRO. true Enable internal 16kHz free running oscillator. false Disable internal 16kHz free running oscillator.

static bool VBAT_CheckFRO16kEnabled ( VBAT_Type * base )

inlinestatic

Parameters

base	VBAT peripheral base address.

Return values

true	The internal 16kHz Free running oscillator is enabled.
false	The internal 16kHz Free running oscillator is enabled.

static void VBAT_UngateFRO16k	(	VBAT_Type *	base,
		uint8_t	connectionsMask
	)

inlinestatic

Parameters

base	VBAT peripheral base address.
connectionsMask	The mask of modules that FRO16k is connected, should be the OR'ed value of vbat_clock_enable_t.

static void VBAT_GateFRO16k	(	VBAT_Type *	base,
		uint8_t	connectionsMask
	)

inlinestatic

Parameters

base	VBAT peripheral base address.
connectionsMask	The OR'ed value of vbat_clock_enable_t.

static void VBAT_LockFRO16kSettings ( VBAT_Type * base )

inlinestatic

Note: Please note that the operation to ungate/gate FRO 16kHz output clock can not be locked by this function.

Parameters

base	VBAT peripheral base address.

static bool VBAT_CheckFRO16kSettingsLocked ( VBAT_Type * base )

inlinestatic

Parameters

base	VBAT peripheral base address.

Returns: true in case of FRO16k settings are locked, false in case of FRO16k settings are not locked.

Overview

FRO16K Control Interfaces

OSC32K Control Interfaces

RAM_LDO Control Interfaces

Bandgap Timer Control Interfaces

Status, Interrupt, Wakeup Control Interfaces

Switch Control Interfaces

Data Structures

Enumerations

Driver version