Overview

The MCUXpresso SDK provides a driver for the Real Time Clock (RTC).

Function groups

The RTC driver supports operating the module as a time counter.

Initialization and deinitialization

The function RTC_Init() initializes the RTC with specified configurations. The function RTC_GetDefaultConfig() gets the default configurations.

The function RTC_Deinit() disables the RTC timer and disables the module clock.

Set & Get Datetime

The function RTC_SetDatetime() sets the timer period in seconds. User passes in the details in date & time format by using the below data structure.

Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/rtc The function RTC_GetDatetime() reads the current timer value in seconds, converts it to date & time format and stores it into a datetime structure passed in by the user.

Set & Get Alarm

The function RTC_SetAlarm() sets the alarm time period in seconds. User passes in the details in date & time format by using the datetime data structure.

The function RTC_GetAlarm() reads the alarm time in seconds, converts it to date & time format and stores it into a datetime structure passed in by the user.

Start & Stop timer

The function RTC_StartTimer() starts the RTC time counter.

The function RTC_StopTimer() stops the RTC time counter.

Status

Provides functions to get and clear the RTC status.

Interrupt

Provides functions to enable/disable RTC interrupts and get current enabled interrupts.

High resolution timer

Provides functions to enable high resolution timer and set and get the wake time.

Typical use case

RTC tick example

Example to set the RTC current time and trigger an alarm. Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/rtc

Files
file	fsl_rtc.h

Data Structures
struct	_rtc_datetime
	Structure is used to hold the date and time. More...

Typedefs
typedef enum _rtc_interrupt_enable	rtc_interrupt_enable_t
	List of RTC interrupts.

typedef enum _rtc_status_flags	rtc_status_flags_t
	List of RTC flags.

typedef struct _rtc_datetime	rtc_datetime_t
	Structure is used to hold the date and time.

Enumerations
enum	_rtc_interrupt_enable { kRTC_AlarmInterruptEnable = RTC_CTRL_ALARMDPD_EN_MASK, kRTC_WakeupInterruptEnable = RTC_CTRL_WAKEDPD_EN_MASK }
	List of RTC interrupts. More...

enum	_rtc_status_flags { kRTC_AlarmFlag = RTC_CTRL_ALARM1HZ_MASK, kRTC_WakeupFlag = RTC_CTRL_WAKE1KHZ_MASK }
	List of RTC flags. More...

Functions
static void	RTC_SetSecondsTimerMatch (RTC_Type *base, uint32_t matchValue)
	Set the RTC seconds timer (1HZ) MATCH value. More...

static uint32_t	RTC_GetSecondsTimerMatch (RTC_Type *base)
	Read actual RTC seconds timer (1HZ) MATCH value. More...

static void	RTC_SetSecondsTimerCount (RTC_Type *base, uint32_t countValue)
	Set the RTC seconds timer (1HZ) COUNT value. More...

static uint32_t	RTC_GetSecondsTimerCount (RTC_Type *base)
	Read the actual RTC seconds timer (1HZ) COUNT value. More...

static void	RTC_SetWakeupCount (RTC_Type *base, uint16_t wakeupValue)
	Enable the RTC wake-up timer (1KHZ) and set countdown value to the RTC WAKE register. More...

static uint16_t	RTC_GetWakeupCount (RTC_Type *base)
	Read the actual value from the WAKE register value in RTC wake-up timer (1KHZ) More...

static void	RTC_Reset (RTC_Type *base)
	Perform a software reset on the RTC module. More...

Driver version
#define	FSL_RTC_DRIVER_VERSION (MAKE_VERSION(2, 2, 0))
	Version 2.2.0.

Initialization and deinitialization
void	RTC_Init (RTC_Type *base)
	Un-gate the RTC clock and enable the RTC oscillator. More...

static void	RTC_Deinit (RTC_Type *base)
	Stop the timer and gate the RTC clock. More...

Current Time & Alarm
status_t	RTC_SetDatetime (RTC_Type base, const rtc_datetime_t datetime)
	Set the RTC date and time according to the given time structure. More...

void	RTC_GetDatetime (RTC_Type base, rtc_datetime_t datetime)
	Get the RTC time and stores it in the given time structure. More...

status_t	RTC_SetAlarm (RTC_Type base, const rtc_datetime_t alarmTime)
	Set the RTC alarm time. More...

void	RTC_GetAlarm (RTC_Type base, rtc_datetime_t datetime)
	Return the RTC alarm time. More...

RTC wake-up timer (1KHZ) Enable
static void	RTC_EnableWakeupTimer (RTC_Type *base, bool enable)
	Enable the RTC wake-up timer (1KHZ). More...

static uint32_t	RTC_GetEnabledWakeupTimer (RTC_Type *base)
	Get the enabled status of the RTC wake-up timer (1KHZ). More...

SUBSEC counter
static void	RTC_EnableSubsecCounter (RTC_Type *base, bool enable)
	Enable the RTC Sub-second counter (32KHZ). More...

static uint32_t	RTC_GetSubsecValue (const RTC_Type *base)
	A read of 32KHZ sub-seconds counter. More...

Interrupt Interface
static void	RTC_EnableWakeUpTimerInterruptFromDPD (RTC_Type *base, bool enable)
	Enable the wake-up timer interrupt from deep power down mode. More...

static void	RTC_EnableAlarmTimerInterruptFromDPD (RTC_Type *base, bool enable)
	Enable the alarm timer interrupt from deep power down mode. More...

static void	RTC_EnableInterrupts (RTC_Type *base, uint32_t mask)
	Enables the selected RTC interrupts. More...

static void	RTC_DisableInterrupts (RTC_Type *base, uint32_t mask)
	Disables the selected RTC interrupts. More...

static uint32_t	RTC_GetEnabledInterrupts (RTC_Type *base)
	Get the enabled RTC interrupts. More...

Status Interface
static uint32_t	RTC_GetStatusFlags (RTC_Type *base)
	Get the RTC status flags. More...

static void	RTC_ClearStatusFlags (RTC_Type *base, uint32_t mask)
	Clear the RTC status flags. More...

Timer Enable
static void	RTC_EnableTimer (RTC_Type *base, bool enable)
	Enable the RTC timer counter. More...

static void	RTC_StartTimer (RTC_Type *base)
	Starts the RTC time counter. More...

static void	RTC_StopTimer (RTC_Type *base)
	Stops the RTC time counter. More...

Data Structure Documentation

struct _rtc_datetime

Data Fields
uint16_t	year
	Range from 1970 to 2099. More...

uint8_t	month
	Range from 1 to 12. More...

uint8_t	day
	Range from 1 to 31 (depending on month). More...

uint8_t	hour
	Range from 0 to 23. More...

uint8_t	minute
	Range from 0 to 59. More...

uint8_t	second
	Range from 0 to 59. More...

Field Documentation

uint16_t _rtc_datetime::year

uint8_t _rtc_datetime::month

uint8_t _rtc_datetime::day

uint8_t _rtc_datetime::hour

uint8_t _rtc_datetime::minute

uint8_t _rtc_datetime::second

Enumeration Type Documentation

enum _rtc_interrupt_enable

Enumerator
kRTC_AlarmInterruptEnable	Alarm interrupt.
kRTC_WakeupInterruptEnable	Wake-up interrupt.

enum _rtc_status_flags

Enumerator
kRTC_AlarmFlag	Alarm flag.
kRTC_WakeupFlag	1kHz wake-up timer flag

Function Documentation

void RTC_Init ( RTC_Type * base )

Note: This API should be called at the beginning of the application using the RTC driver.

Parameters

base	RTC peripheral base address

static void RTC_Deinit ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

status_t RTC_SetDatetime	(	RTC_Type *	base,
		const rtc_datetime_t *	datetime
	)

The RTC counter must be stopped prior to calling this function as writes to the RTC seconds register will fail if the RTC counter is running.

Parameters

base	RTC peripheral base address
datetime	Pointer to structure where the date and time details to set are stored

Returns: kStatus_Success: Success in setting the time and starting the RTC kStatus_InvalidArgument: Error because the datetime format is incorrect

void RTC_GetDatetime	(	RTC_Type *	base,
		rtc_datetime_t *	datetime
	)

Parameters

base	RTC peripheral base address
datetime	Pointer to structure where the date and time details are stored.

status_t RTC_SetAlarm	(	RTC_Type *	base,
		const rtc_datetime_t *	alarmTime
	)

The function checks whether the specified alarm time is greater than the present time. If not, the function does not set the alarm and returns an error.

Parameters

base	RTC peripheral base address
alarmTime	Pointer to structure where the alarm time is stored.

Returns: kStatus_Success: success in setting the RTC alarm kStatus_InvalidArgument: Error because the alarm datetime format is incorrect kStatus_Fail: Error because the alarm time has already passed

void RTC_GetAlarm	(	RTC_Type *	base,
		rtc_datetime_t *	datetime
	)

Parameters

base	RTC peripheral base address
datetime	Pointer to structure where the alarm date and time details are stored.

static void RTC_EnableWakeupTimer	(	RTC_Type *	base,
		bool	enable
	)

inlinestatic

After calling this function, the RTC driver will use/un-use the RTC wake-up (1KHZ) at the same time.

Parameters

base	RTC peripheral base address
enable	Use/Un-use the RTC wake-up timer. true: Use RTC wake-up timer at the same time. false: Un-use RTC wake-up timer, RTC only use the normal seconds timer by default.

static uint32_t RTC_GetEnabledWakeupTimer ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: The enabled status of RTC wake-up timer (1KHZ).

static void RTC_EnableSubsecCounter	(	RTC_Type *	base,
		bool	enable
	)

inlinestatic

Note: Only enable sub-second counter after RTC_ENA bit has been set to 1.

Parameters

base	RTC peripheral base address
enable	Enable/Disable RTC sub-second counter. true: Enable RTC sub-second counter. false: Disable RTC sub-second counter.

static uint32_t RTC_GetSubsecValue ( const RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: Current value of the SUBSEC register

static void RTC_SetSecondsTimerMatch	(	RTC_Type *	base,
		uint32_t	matchValue
	)

inlinestatic

Parameters

base	RTC peripheral base address
matchValue	The value to be set into the RTC MATCH register

static uint32_t RTC_GetSecondsTimerMatch ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: The actual RTC seconds timer (1HZ) MATCH value.

static void RTC_SetSecondsTimerCount	(	RTC_Type *	base,
		uint32_t	countValue
	)

inlinestatic

Parameters

base	RTC peripheral base address
countValue	The value to be loaded into the RTC COUNT register

static uint32_t RTC_GetSecondsTimerCount ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: The actual RTC seconds timer (1HZ) COUNT value.

static void RTC_SetWakeupCount	(	RTC_Type *	base,
		uint16_t	wakeupValue
	)

inlinestatic

Parameters

base	RTC peripheral base address
wakeupValue	The value to be loaded into the WAKE register in RTC wake-up timer (1KHZ).

static uint16_t RTC_GetWakeupCount ( RTC_Type * base )

inlinestatic

Read the WAKE register twice and compare the result, if the value match,the time can be used.

Parameters

base	RTC peripheral base address

Returns: The actual value of the WAKE register value in RTC wake-up timer (1KHZ).

static void RTC_EnableWakeUpTimerInterruptFromDPD	(	RTC_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	RTC peripheral base address
enable	Enable/Disable wake-up timer interrupt from deep power down mode. true: Enable wake-up timer interrupt from deep power down mode. false: Disable wake-up timer interrupt from deep power down mode.

static void RTC_EnableAlarmTimerInterruptFromDPD	(	RTC_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	RTC peripheral base address
enable	Enable/Disable alarm timer interrupt from deep power down mode. true: Enable alarm timer interrupt from deep power down mode. false: Disable alarm timer interrupt from deep power down mode.

static void RTC_EnableInterrupts	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Deprecated:: Do not use this function. It has been superceded by RTC_EnableAlarmTimerInterruptFromDPD and RTC_EnableWakeUpTimerInterruptFromDPD

Parameters

base	RTC peripheral base address
mask	The interrupts to enable. This is a logical OR of members of the enumeration rtc_interrupt_enable_t

static void RTC_DisableInterrupts	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Deprecated:: Do not use this function. It has been superceded by RTC_EnableAlarmTimerInterruptFromDPD and RTC_EnableWakeUpTimerInterruptFromDPD

Parameters

base	RTC peripheral base address
mask	The interrupts to enable. This is a logical OR of members of the enumeration rtc_interrupt_enable_t

static uint32_t RTC_GetEnabledInterrupts ( RTC_Type * base )

inlinestatic

Deprecated:: Do not use this function. It will be deleted in next release version.

Parameters

base	RTC peripheral base address

Returns: The enabled interrupts. This is the logical OR of members of the enumeration rtc_interrupt_enable_t

static uint32_t RTC_GetStatusFlags ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: The status flags. This is the logical OR of members of the enumeration rtc_status_flags_t

static void RTC_ClearStatusFlags	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	RTC peripheral base address
mask	The status flags to clear. This is a logical OR of members of the enumeration rtc_status_flags_t

static void RTC_EnableTimer	(	RTC_Type *	base,
		bool	enable
	)

inlinestatic

After calling this function, the RTC inner counter increments once a second when only using the RTC seconds timer (1hz), while the RTC inner wake-up timer countdown once a millisecond when using RTC wake-up timer (1KHZ) at the same time. RTC timer contain two timers, one is the RTC normal seconds timer, the other one is the RTC wake-up timer, the RTC enable bit is the master switch for the whole RTC timer, so user can use the RTC seconds (1HZ) timer independly, but they can't use the RTC wake-up timer (1KHZ) independently.

Parameters

base	RTC peripheral base address
enable	Enable/Disable RTC Timer counter. true: Enable RTC Timer counter. false: Disable RTC Timer counter.

static void RTC_StartTimer ( RTC_Type * base )

inlinestatic

Deprecated:: Do not use this function. It has been superceded by RTC_EnableTimer

After calling this function, the timer counter increments once a second provided SR[TOF] or SR[TIF] are not set.

Parameters

base	RTC peripheral base address

static void RTC_StopTimer ( RTC_Type * base )

inlinestatic

Deprecated:: Do not use this function. It has been superceded by RTC_EnableTimer

RTC's seconds register can be written to only when the timer is stopped.

Parameters

base	RTC peripheral base address

static void RTC_Reset ( RTC_Type * base )

inlinestatic

This resets all RTC registers to their reset value. The bit is cleared by software explicitly clearing it.

Parameters

base	RTC peripheral base address

Overview

Function groups

Initialization and deinitialization

Set & Get Datetime

Set & Get Alarm

Start & Stop timer

Status

Interrupt

High resolution timer

Typical use case

RTC tick example

Files

Data Structures

Typedefs

Enumerations

Functions

Driver version

Initialization and deinitialization

Current Time & Alarm

RTC wake-up timer (1KHZ) Enable

SUBSEC counter

Interrupt Interface

Status Interface

Timer Enable

Data Structure Documentation

Data Fields

Field Documentation

Enumeration Type Documentation

Function Documentation