Real-time task scheduling

Files
file	rtimer.h

Classes
struct	rtimer
	Representation of a real-time task. More...

Macros
#define	RTIMER_CLOCK_LT(a, b)   ((signed short)((a)-(b)) < 0)
#define	RTIMER_NOW()
	Get the current clock time. More...
#define	RTIMER_TIME(task)
	Get the time that a task last was executed. More...
#define	RTIMER_SECOND   RTIMER_ARCH_SECOND

Typedefs
typedef unsigned short	rtimer_clock_t
typedef void(*	rtimer_callback_t) (struct rtimer *t, void *ptr)

Enumerations
enum	{ RTIMER_OK , RTIMER_ERR_FULL , RTIMER_ERR_TIME , RTIMER_ERR_ALREADY_SCHEDULED }

Functions
void	rtimer_init (void)
	Initialize the real-time scheduler. More...
int	rtimer_set (struct rtimer *task, rtimer_clock_t time, rtimer_clock_t duration, rtimer_callback_t func, void *ptr)
	Post a real-time task. More...
void	rtimer_run_next (void)
	Execute the next real-time task and schedule the next task, if any. More...
void	rtimer_arch_init (void)
void	rtimer_arch_schedule (rtimer_clock_t t)

Detailed Description

The real-time module handles the scheduling and execution of real-time tasks (with predictable execution times).

Macro Definition Documentation

RTIMER_CLOCK_LT

#define RTIMER_CLOCK_LT	(		a,
			b
	)		((signed short)((a)-(b)) < 0)

RTIMER_NOW

#define RTIMER_NOW

(

)

Get the current clock time.

Returns

The current time

        This function returns what the real-time module thinks
        is the current time. The current time is used to set
        the timeouts for real-time tasks.

RTIMER_SECOND

#define RTIMER_SECOND   RTIMER_ARCH_SECOND

RTIMER_TIME

#define RTIMER_TIME

(

task

)

Get the time that a task last was executed.

Parameters

task

The task

Returns

The time that a task last was executed

        This function returns the time that the task was last
        executed. This typically is used to get a periodic
        execution of a task without clock drift.

Typedef Documentation

rtimer_callback_t

typedef void(* rtimer_callback_t) (struct rtimer *t, void *ptr)

rtimer_clock_t

typedef unsigned short rtimer_clock_t

Enumeration Type Documentation

anonymous enum

anonymous enum

Enumerator
RTIMER_OK
RTIMER_ERR_FULL
RTIMER_ERR_TIME
RTIMER_ERR_ALREADY_SCHEDULED

Function Documentation

rtimer_arch_init()

void rtimer_arch_init

(

void

)

rtimer_arch_schedule()

void rtimer_arch_schedule

(

rtimer_clock_t

t

)

rtimer_init()

void rtimer_init

(

void

)

Initialize the real-time scheduler.

        This function initializes the real-time scheduler and
        must be called at boot-up, before any other functions
        from the real-time scheduler is called.

rtimer_run_next()

void rtimer_run_next

(

void

)

Execute the next real-time task and schedule the next task, if any.

        This function is called by the architecture dependent
        code to execute and schedule the next real-time task.

rtimer_set()

int rtimer_set	(	struct rtimer *	task,
		rtimer_clock_t	time,
		rtimer_clock_t	duration,
		rtimer_callback_t	func,
		void *	ptr
	)

Post a real-time task.

Parameters

task	A pointer to the task variable previously declared with RTIMER_TASK().
time	The time when the task is to be executed.
duration	Unused argument.
func	A function to be called when the task is executed.
ptr	An opaque pointer that will be supplied as an argument to the callback function.

Returns

Non-zero (true) if the task could be scheduled, zero (false) if the task could not be scheduled.

This function schedules a real-time task at a specified time in the future.