Real-time task scheduling

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

Data Structures
struct	rtimer
	Representation of a real-time task. More...
Files
file	rtimer.c
	Implementation of the architecture-agnostic parts of the real-time timer module.
file	rtimer.h
	Header file for the real-time timer module.
Defines
#define	RTIMER_NOW()
	Get the current clock time.
#define	RTIMER_TIME(task)
	Get the time that a task last was executed.
Functions
void	rtimer_init (void)
	Initialize the real-time scheduler.
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.
void	rtimer_run_next (void)
	Execute the next real-time task and schedule the next task, if any.

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Detailed Description

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

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Define Documentation

#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.

Examples:

example-rudolph1.c.

Definition at line 133 of file rtimer.h.

Referenced by main().

#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.

Examples:

example-rudolph1.c.

Definition at line 146 of file rtimer.h.

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Function Documentation

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.

Definition at line 63 of file rtimer.c.

Referenced by main().

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.

Definition at line 94 of file rtimer.c.

References NULL.

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.

Examples:

example-rudolph1.c.

Definition at line 69 of file rtimer.c.

References NULL.

Referenced by main().