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.

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.

Typical use case

RTC tick example

Example to set the RTC current time and trigger an sleep interrupt. 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_t
	Structure is used to hold the date and time. More...

Macros
#define	RTC_SYNC_TIME_OUT_TICKS ((SystemCoreClock * (3 + 1)) / RTC_TFRO_FREQ)
	Time-out ticks is (in ARM clock ticks) that a bus synchronization wait should take. More...

Enumerations
enum	rtc_interrupt_enable_t { kRTC_CountDownInterruptEnable = RTC_IMIS_IE_MASK }
	List of RTC interrupts. More...

enum	rtc_status_flags_t { kRTC_EnabledFlag = RTC_SR_EN_MASK, kRTC_FreezedFlag = RTC_SR_FREEZE_MASK, kRTC_RunFlag = RTC_SR_RUN_MASK }
	List of RTC flags. More...

enum	rtc_raw_interrupt_status_t { kRTC_CountDownRawStatus = RTC_RIS_RIS_MASK }
	List of RTC raw interrupt status. More...

enum	rtc_masked_interrupt_status_t { kRTC_CountDownMaskedStatus = RTC_MIS_MIS_MASK }
	List of RTC masked interrupt status. More...

Driver version
#define	FSL_RTC_DRIVER_VERSION (MAKE_VERSION(2, 0, 1))
	Version 2.0.1.

Bus synchornous operations.
void	RTC_WriteRegister (__IO uint32_t *reg, uint32_t value)
	Write value to RTC register. More...

uint32_t	RTC_ReadRegister (__I uint32_t *reg)
	Read data from RTC register. More...

Initialization and deinitialization
void	RTC_Init (RTC_Type base, rtc_config_t config)
	Initalize the RTC mudule. More...

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

void	RTC_GetDefaultConfig (RTC_Type base, rtc_config_t config)
	Get default config for RTC setting. More...

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

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

static void	RTC_SetSleepTime (RTC_Type *base, uint32_t value)
	Sets the RTC sleep time. More...

static uint32_t	RTC_GetSleepTime (RTC_Type *base)
	Returns the current RTC sleep time value. More...

Interrupt Interface
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...

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

static uint32_t	RTC_GetRawInterruptStatus (RTC_Type *base)
	Gets the RTC Raw interrupt status. More...

static uint32_t	RTC_GetMaskedInterruptStatus (RTC_Type *base)
	Gets the RTC status flags. More...

static void	RTC_ClearMaskedInterruptStatus (RTC_Type *base, uint32_t mask)
	Clear masked interrupt status. More...

Timer Start and Stop
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...

void	RTC_EnableSleepAutoStart (RTC_Type *base, bool enable)
	Enable the sleep count down auto Start. More...

static void	RTC_StartSleep (RTC_Type *base)
	Start the count down manually. More...

static void	RTC_SetCalibrationValue (RTC_Type *base, uint32_t value)
	Set calibration value. More...

static uint32_t	RTC_GetCalibrationValue (RTC_Type *base)
	Get the calibration value from register. More...

Data Structure Documentation

struct rtc_datetime_t

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_t::year

uint8_t rtc_datetime_t::month

uint8_t rtc_datetime_t::day

uint8_t rtc_datetime_t::hour

uint8_t rtc_datetime_t::minute

uint8_t rtc_datetime_t::second

Macro Definition Documentation

#define RTC_SYNC_TIME_OUT_TICKS ((SystemCoreClock * (3 + 1)) / RTC_TFRO_FREQ)

Worst-case wait is 3 TFRO ticks. Worst case ARM speed is full SFRO (no divider). Since the TFRO could be somewhat slower than spec'd, and the SFRO somewhat faster, we add 33% as margin - it is just for an emergency time-out.

Enumeration Type Documentation

enum rtc_interrupt_enable_t

Enumerator
kRTC_CountDownInterruptEnable	Count down interrupt.

enum rtc_status_flags_t

Enumerator
kRTC_EnabledFlag	Flag for RTC enabled or not.
kRTC_FreezedFlag	Flag for RTC freezed or not.
kRTC_RunFlag	Flag for RTC running status.

enum rtc_raw_interrupt_status_t

Enumerator
kRTC_CountDownRawStatus	Raw interrupt status for count down finish.

enum rtc_masked_interrupt_status_t

Enumerator
kRTC_CountDownMaskedStatus	Masked interrupt status for count down finish.

Function Documentation

void RTC_WriteRegister	(	__IO uint32_t *	reg,
		uint32_t	value
	)

Note: This API will write data to RTC register, all bus synchornous operation will be done.

uint32_t RTC_ReadRegister ( __I uint32_t * reg )

Note: This API will read the RTC's register value.

void RTC_Init	(	RTC_Type *	base,
		rtc_config_t *	config
	)

Note: This API should be called at the beginning of the application using the RTC driver. This API will help configure the calibration value, count down auto start, enable RTC timer and the initialized date for counting.

Parameters

base	RTC peripheral base address
config	configuration for initializing RTC.

static void RTC_Deinit ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

void RTC_GetDefaultConfig	(	RTC_Type *	base,
		rtc_config_t *	config
	)

   This configure structure will help setup calibration value, formated date value.
   And set if enable RTC timer and count down auto start function.

Parameters

base	RTC peripheral base address
config	configure structure for setting RTC module. refer to .

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.

static void RTC_SetSleepTime	(	RTC_Type *	base,
		uint32_t	value
	)

inlinestatic

The function will set the sleep time for counting down, if the value in SLEEPT register equals to 0, an interrupt will be generated if this interrupt is enabled.

Parameters

base	RTC peripheral base address
value	sleep time, uint is seconds.

static uint32_t RTC_GetSleepTime ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Returns: The sleep remaining in register.

static void RTC_EnableInterrupts	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	RTC peripheral base address
mask	The interrupts to enable. Refer to the enumeration rtc_interrupt_enable_t

static void RTC_DisableInterrupts	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

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_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 uint32_t RTC_GetRawInterruptStatus ( 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 uint32_t RTC_GetMaskedInterruptStatus ( 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_ClearMaskedInterruptStatus	(	RTC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	RTC peripheral base address

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

static void RTC_StartTimer ( RTC_Type * base )

inlinestatic

After calling this function, the timer counter increments once a second.

Parameters

base	RTC peripheral base address

static void RTC_StopTimer ( RTC_Type * base )

inlinestatic

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

Parameters

base	RTC peripheral base address

void RTC_EnableSleepAutoStart	(	RTC_Type *	base,
		bool	enable
	)

Parameters

base	RTC peripheral base address
enable	1 for enable, 0 for disable.

static void RTC_StartSleep ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

static void RTC_SetCalibrationValue	(	RTC_Type *	base,
		uint32_t	value
	)

inlinestatic

   The calibration value decide the number of TFRO clock pulses in one tick

Parameters

base	RTC peripheral base address
value	The value to be set.

static uint32_t RTC_GetCalibrationValue ( RTC_Type * base )

inlinestatic

Parameters

base	RTC peripheral base address

Overview

Function groups

Initialization and deinitialization

Set & Get Datetime

Start & Stop timer

Status

Interrupt

Typical use case

RTC tick example

Files

Data Structures

Macros

Enumerations

Driver version

Bus synchornous operations.

Initialization and deinitialization

Current Time date.

Interrupt Interface

Status Interface

Timer Start and Stop

Data Structure Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation