Clock and Timer Management

Data Structures
struct	rt_timer
Defines
#define	RT_TIMER_FLAG_DEACTIVATED   0x0
#define	RT_TIMER_FLAG_ACTIVATED   0x1
#define	RT_TIMER_FLAG_ONE_SHOT   0x0
#define	RT_TIMER_FLAG_PERIODIC   0x2
#define	RT_TIMER_FLAG_HARD_TIMER   0x0
#define	RT_TIMER_FLAG_SOFT_TIMER   0x4
#define	RT_TIMER_CTRL_SET_TIME   0x0
#define	RT_TIMER_CTRL_GET_TIME   0x1
#define	RT_TIMER_CTRL_SET_ONESHOT   0x2
#define	RT_TIMER_CTRL_SET_PERIODIC   0x3
Functions
rt_tick_t	rt_tick_get (void)
void	rt_tick_set (rt_tick_t tick)
void	rt_tick_increase (void)
rt_tick_t	rt_tick_from_millisecond (rt_uint32_t ms)
void	rt_timer_init (rt_timer_t timer, const char *name, void(*timeout)(void *parameter), void *parameter, rt_tick_t time, rt_uint8_t flag)
rt_err_t	rt_timer_detach (rt_timer_t timer)
rt_timer_t	rt_timer_create (const char *name, void(*timeout)(void *parameter), void *parameter, rt_tick_t time, rt_uint8_t flag)
rt_err_t	rt_timer_delete (rt_timer_t timer)
rt_err_t	rt_timer_start (rt_timer_t timer)
rt_err_t	rt_timer_stop (rt_timer_t timer)
rt_err_t	rt_timer_control (rt_timer_t timer, rt_uint8_t cmd, void *arg)
void	rt_timer_check (void)
void	rt_system_tick_init (void)
void	rt_system_timer_init (void)
void	rt_system_timer_thread_init (void)
void	rt_timer_timeout_sethook (void(*hook)(struct rt_timer *timer))

---

Detailed Description

* RT-Thread uses clock tick to implement shared time-slice scheduling.

The timing sensitivity of thread is implemented by timers. The timer can be set as one-shot or periodic timeout.

---

Define Documentation

#define RT_TIMER_FLAG_DEACTIVATED   0x0

clock & timer macros timer is deactive

#define RT_TIMER_FLAG_ACTIVATED   0x1

timer is active

#define RT_TIMER_FLAG_ONE_SHOT   0x0

one shot timer

#define RT_TIMER_FLAG_PERIODIC   0x2

periodic timer

#define RT_TIMER_FLAG_HARD_TIMER   0x0

hard timer,the timer's callback function will be called in tick isr.

#define RT_TIMER_FLAG_SOFT_TIMER   0x4

soft timer,the timer's callback function will be called in timer thread.

#define RT_TIMER_CTRL_SET_TIME   0x0

set timer control command

#define RT_TIMER_CTRL_GET_TIME   0x1

get timer control command

#define RT_TIMER_CTRL_SET_ONESHOT   0x2

change timer to one shot

#define RT_TIMER_CTRL_SET_PERIODIC   0x3

change timer to periodic

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Function Documentation

rt_tick_t rt_tick_get

(

void

)

This function will return current tick from operating system startup

Returns:

current tick

void rt_tick_set

(

rt_tick_t

tick

)

This function will set current tick

void rt_tick_increase

(

void

)

This function will notify kernel there is one tick passed. Normally, this function is invoked by clock ISR.

rt_tick_t rt_tick_from_millisecond

(

rt_uint32_t

ms

)

This function will calculate the tick from millisecond.

Parameters:

ms	the specified millisecond

Returns:

the calculated tick

void rt_timer_init	(	rt_timer_t	timer,
		const char *	name,
		void(*)(void *parameter)	timeout,
		void *	parameter,
		rt_tick_t	time,
		rt_uint8_t	flag
	)

This function will initialize a timer, normally this function is used to initialize a static timer object.

Parameters:

timer	the static timer object
name	the name of timer
timeout	the timeout function
parameter	the parameter of timeout function
time	the tick of timer
flag	the flag of timer

rt_err_t rt_timer_detach

(

rt_timer_t

timer

)

This function will detach a timer from timer management.

Parameters:

timer

the static timer object

Returns:

the operation status, RT_EOK on OK; RT_ERROR on error

rt_timer_t rt_timer_create	(	const char *	name,
		void(*)(void *parameter)	timeout,
		void *	parameter,
		rt_tick_t	time,
		rt_uint8_t	flag
	)

This function will create a timer

Parameters:

name	the name of timer
timeout	the timeout function
parameter	the parameter of timeout function
time	the tick of timer
flag	the flag of timer

Returns:

the created timer object

rt_err_t rt_timer_delete

(

rt_timer_t

timer

)

This function will delete a timer and release timer memory

Parameters:

timer

the timer to be deleted

Returns:

the operation status, RT_EOK on OK; RT_ERROR on error

rt_err_t rt_timer_start

(

rt_timer_t

timer

)

This function will start the timer

Parameters:

timer

the timer to be started

Returns:

the operation status, RT_EOK on OK, -RT_ERROR on error

rt_err_t rt_timer_stop

(

rt_timer_t

timer

)

This function will stop the timer

Parameters:

timer

the timer to be stopped

Returns:

the operation status, RT_EOK on OK, -RT_ERROR on error

rt_err_t rt_timer_control	(	rt_timer_t	timer,
		rt_uint8_t	cmd,
		void *	arg
	)

This function will get or set some options of the timer

Parameters:

timer	the timer to be get or set
cmd	the control command
arg	the argument

Returns:

RT_EOK

void rt_timer_check

(

void

)

This function will check timer list, if a timeout event happens, the corresponding timeout function will be invoked.

Note:

this function shall be invoked in operating system timer interrupt.

void rt_system_tick_init

(

void

)

This function will init system tick and set it to zero.

void rt_system_timer_init

(

void

)

This function will initialize system timer

void rt_system_timer_thread_init

(

void

)

This function will initialize system timer thread

void rt_timer_timeout_sethook

(

void(*)(struct rt_timer *timer)

hook

)

This function will set a hook function, which will be invoked when timer is timeout.

Parameters:

hook	the hook function