RIT: Repetitive Interrupt Timer

Overview

The MCUXpresso SDK provides a driver for the Repetitive Interrupt Timer (RIT) of MCUXpresso SDK devices.

Function groups

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

Initialization and deinitialization

The function RIT_Init() initializes the RIT with specified configurations. The function RIT_GetDefaultConfig() gets the default configurations. The initialization function configures the RIT operation normally in debug mode.

The function RIT_Deinit() disables the RIT timers and disables the module clock.

Timer read and write Operations

The function RIT_SetTimerCompare() sets the timer period in units of count. Timers counts from 0 to the count value set here. The function RIT_SetMaskBit() sets some bit which will be ignored in comparison between the compare and counter register.

The function RIT_GetCurrentTimerCount() reads the current timer counting value. This function returns the real-time timer counting value, in a range from 0 to a timer period.

The timer period operation functions takes the count value in ticks. User can call the utility macros provided in fsl_common.h to convert to microseconds or milliseconds

Start and Stop timer operations

The function RIT_StartTimer() starts the timer counting. After calling this function, the timer counts up to the counter value set earlier by using the RIT_SetTimerCompare() function. Each time the timer reaches the count value, it generates a trigger pulse and sets the interrupt flag and set the counter to zero/continue counting when RIT_ClearCounter() set the Timer clear enable/disable.

The function RIT_StopTimer() stops the timer counting.// resets the timer's counter register.

clear the count operations

The function RIT_ClearCounter() set the cuonter register to continue counting or clear the counter to zero when the the counter value equals the masked compare value specified by the contents of COMPVAL/COMPVAL_H and MASK/MASK_H registers.

Status

Provides functions to get and clear the RIT status.

Typical use case

RIT tick example

Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/rit

Data Structures
struct	rit_config_t
	RIT config structure. More...

Enumerations
enum	rit_status_flags_t { kRIT_TimerFlag = RIT_CTRL_RITINT_MASK }
	List of RIT status flags. More...

Driver version
#define	FSL_RIT_DRIVER_VERSION   (MAKE_VERSION(2, 0, 0))
	Version 2.0.0.

Initialization and deinitialization
void	RIT_Init (RIT_Type *base, const rit_config_t *config)
	Ungates the RIT clock, enables the RIT module, and configures the peripheral for basic operations. More...
void	RIT_Deinit (RIT_Type *base)
	Gates the RIT clock and disables the RIT module. More...
void	RIT_GetDefaultConfig (rit_config_t *config)
	Fills in the RIT configuration structure with the default settings. More...

Status Interface
static uint32_t	RIT_GetStatusFlags (RIT_Type *base)
	Gets the RIT status flags. More...
static void	RIT_ClearStatusFlags (RIT_Type *base, uint32_t mask)
	Clears the RIT status flags. More...

Read and Write the timer period
void	RIT_SetTimerCompare (RIT_Type *base, uint64_t count)
	Sets the timer period in units of count. More...
void	RIT_SetMaskBit (RIT_Type *base, uint64_t count)
	Sets the mask bit of count compare. More...
uint64_t	RIT_GetCompareTimerCount (RIT_Type *base)
	Reads the current timer counting value of compare register. More...
uint64_t	RIT_GetCounterTimerCount (RIT_Type *base)
	Reads the current timer counting value of counter register. More...
uint64_t	RIT_GetMaskTimerCount (RIT_Type *base)
	Reads the current timer counting value of mask register. More...

Timer Start and Stop
static void	RIT_StartTimer (RIT_Type *base)
	Starts the timer counting. More...
static void	RIT_StopTimer (RIT_Type *base)
	Stops the timer counting. More...

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Data Structure Documentation

struct rit_config_t

This structure holds the configuration settings for the RIT peripheral. To initialize this structure to reasonable defaults, call the RIT_GetDefaultConfig() function and pass a pointer to your config structure instance.

The config struct can be made const so it resides in flash

Data Fields
bool	enableRunInDebug
	true: The timer is halted when the processor is halted for debugging. More...

Field Documentation

bool rit_config_t::enableRunInDebug

; false: Debug has no effect on the timer operation.

Enumeration Type Documentation

enum rit_status_flags_t

Enumerator
kRIT_TimerFlag	Timer flag.

Function Documentation

void RIT_Init	(	RIT_Type *	base,
		const rit_config_t *	config
	)

Note

This API should be called at the beginning of the application using the RIT driver.

Parameters

base	RIT peripheral base address
config	Pointer to the user's RIT config structure

void RIT_Deinit

(

RIT_Type *

base

)

Parameters

base	RIT peripheral base address

void RIT_GetDefaultConfig

(

rit_config_t *

config

)

The default values are as follows.

*     config->enableRunInDebug = false;
* 

Parameters

config

Pointer to the onfiguration structure.

static uint32_t RIT_GetStatusFlags ( RIT_Type *  base )

inlinestatic

Parameters

base	RIT peripheral base address

Returns

The status flags. This is the logical OR of members of the enumeration rit_status_flags_t

static void RIT_ClearStatusFlags ( RIT_Type *  base, uint32_t  mask  )

inlinestatic

Parameters

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

void RIT_SetTimerCompare	(	RIT_Type *	base,
		uint64_t	count
	)

Timers begin counting from the value set by this function until it XXXXXXX, then it counting the value again. Software must stop the counter before reloading it with a new value..

Note

Users can call the utility macros provided in fsl_common.h to convert to ticks

Parameters

base	RIT peripheral base address
count	Timer period in units of ticks

void RIT_SetMaskBit	(	RIT_Type *	base,
		uint64_t	count
	)

Timers begin counting from the value set by this function until it XXXXXXX, then it counting the value again. Software must stop the counter before reloading it with a new value..

Note

Users can call the utility macros provided in fsl_common.h to convert to ticks

Parameters

base	RIT peripheral base address
count	Timer period in units of ticks

uint64_t RIT_GetCompareTimerCount

(

RIT_Type *

base

)

This function returns the real-time timer counting value, in a range from 0 to a timer period.

Note

Users can call the utility macros provided in fsl_common.h to convert ticks to usec or msec

Parameters

base	RIT peripheral base address

Returns

Current timer counting value in ticks

uint64_t RIT_GetCounterTimerCount

(

RIT_Type *

base

)

This function returns the real-time timer counting value, in a range from 0 to a timer period.

Note

Users can call the utility macros provided in fsl_common.h to convert ticks to usec or msec

Parameters

base	RIT peripheral base address

Returns

Current timer counting value in ticks

uint64_t RIT_GetMaskTimerCount

(

RIT_Type *

base

)

This function returns the real-time timer counting value, in a range from 0 to a timer period.

Note

Users can call the utility macros provided in fsl_common.h to convert ticks to usec or msec

Parameters

base	RIT peripheral base address

Returns

Current timer counting value in ticks

static void RIT_StartTimer ( RIT_Type *  base )

inlinestatic

After calling this function, timers load initial value(0U), count up to desired value or over-flow then the counter will count up again. Each time a timer reaches desired value, it generates a XXXXXXX and sets XXXXXXX.

Parameters

base	RIT peripheral base address

static void RIT_StopTimer ( RIT_Type *  base )

inlinestatic

This function stop timer counting. Timer reload their new value after the next time they call the RIT_StartTimer.

Parameters

base	RIT peripheral base address
channel	Timer channel number.