Real-time task scheduling

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

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.

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

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

Enumerations
enum	{   RTIMER_OK,   RTIMER_ERR_FULL,   RTIMER_ERR_TIME,   RTIMER_ERR_ALREADY_SCHEDULED }

Functions
void	rtimer_arch_init (void)
void	rtimer_arch_schedule (rtimer_clock_t t)
void	rtimer_init (void)
	Initialize the real-time scheduler. More...
void	rtimer_run_next (void)
	Execute the next real-time task and schedule the next task, if any. 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...

Variables
static struct rtimer *	next_rtimer

#define _DEBUG_   0

#define PRINTF

(

...

)

Referenced by rtimer_set().

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

Referenced by phase_wait(), powercycle(), rtimer_arch_schedule(), schedule_powercycle(), schedule_powercycle_fixed(), send_one_packet(), and send_packet().

#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.

Referenced by echo_reply_callback(), init(), phase_wait(), powercycle(), PROCESS_THREAD(), schedule_powercycle(), schedule_powercycle_fixed(), send_one_packet(), send_packet(), and turn_on().

#define RTIMER_SECOND   RTIMER_ARCH_SECOND

Referenced by echo_reply_callback(), rf212_channel_clear(), rf212_transmit(), rf233_channel_clear(), rf233_transmit(), and simple_udp_ping_get_delay().

#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.

Referenced by schedule_powercycle().

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

typedef unsigned short rtimer_clock_t

anonymous enum

Enumerator
RTIMER_OK
RTIMER_ERR_FULL
RTIMER_ERR_TIME
RTIMER_ERR_ALREADY_SCHEDULED

void rtimer_arch_init

(

void

)

References tc_config::clock_prescaler, tc_config::clock_source, configure_rtc_callbacks(), configure_rtc_count(), tc_config::counter_size, GCLK_GENERATOR_5, ret, rtimer_irq_callback(), tc_config::run_in_standby, SYSTEM_INTERRUPT_PRIORITY_LEVEL_1, system_interrupt_set_priority(), TC_CALLBACK_CC_CHANNEL0, TC_CLOCK_PRESCALER_DIV256, TC_COUNTER_SIZE_32BIT, tc_enable(), tc_enable_callback(), tc_get_config_defaults(), tc_init(), tc_instance, tc_register_callback(), and TIMER.

Referenced by rtimer_init().

void rtimer_arch_schedule

(

rtimer_clock_t

t

)

• set compare match on time t */
• enable interrupts */

References printf, rtimer_arch_now(), RTIMER_CLOCK_LT, RTIMER_COMPENSATION_TICKS, rtimer_run_next(), RTIMER_SYNC_VALUE, TC_COMPARE_CAPTURE_CHANNEL_0, tc_instance, and tc_set_compare_value().

Referenced by rtimer_run_next(), and rtimer_set().

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.

References rtimer_arch_init().

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.

References rtimer::func, next_rtimer, NULL, rtimer::ptr, rtimer_arch_schedule(), and rtimer::time.

Referenced by rtimer_adjust_ticks(), rtimer_arch_schedule(), and rtimer_irq_callback().

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.

References rtimer::func, NULL, PRINTF, rtimer::ptr, ptr, rtimer_arch_schedule(), RTIMER_OK, and rtimer::time.

Referenced by init(), schedule_powercycle(), schedule_powercycle_fixed(), and turn_on().

struct rtimer* next_rtimer

static

Referenced by rtimer_run_next().