timer.c File Reference

Timer Subsystem. More...

Macros
#define	TF_CONTEXT   0x20
	Timer callback expects a context parameter.
#define	TF_OVERFLOW   0x40
	Timer is the special overflow timer.
#define	TF_CALLED   0x80
	Timer has been called once in this interrupt.

Functions
void	timer_init (void)
	Initialize the timer subsystem.
timer_link_t *	new_timer (int ticks, int flags, timer_callback1_t callback)
	Create a new timer and add to list.
timer_link_t *	new_timer_context (int ticks, int flags, timer_callback2_t callback, void *ctx)
	Create a new timer with context and add to list.
void	start_timer (timer_link_t *timer, int ticks, int flags, timer_callback1_t callback)
	Start a timer (not currently in the list)
void	start_timer_context (timer_link_t *timer, int ticks, int flags, timer_callback2_t callback, void *ctx)
	Start a timer (not currently in the list) with context.
void	restart_timer (timer_link_t *timer)
	Reset a timer and add to list.
void	stop_timer (timer_link_t *timer)
	Stop a timer and remove it from the list.
void	delete_timer (timer_link_t *timer)
	Remove a timer from the list and delete it.
void	timer_close (void)
	Free and close the timer subsystem.
long long	timer_ticks (void)
	Return total ticks since timer was initialized, as a 64-bit counter.

Detailed Description

Timer Subsystem.

Function Documentation

timer_init()

void timer_init

(

void

)

Initialize the timer subsystem.

This function will reset the COP0 ticks counter to 0. Even if you later access the hardware counter directly (via TICKS_READ()), it should not be a problem if you call timer_init() early in the application main.

Do not modify the COP0 ticks counter after calling this function. Doing so will impede functionality of the timer module.

The timer subsystem tracks the number of times timer_init is called and will only initialize the subsystem on the first call. This reference count also applies to timer_close, which will only close the subsystem if it is called the same number of times as timer_init.

new_timer()

timer_link_t * new_timer	(	int	ticks,
		int	flags,
		timer_callback1_t	callback
	)

Create a new timer and add to list.

If you need to associate some data with the timer, consider using new_timer_context to include a pointer in the callback.

Parameters

[in]	ticks	Number of ticks before the timer should fire
[in]	flags	Timer flags. See TF_ONE_SHOT, TF_CONTINUOUS and TF_DISABLED
[in]	callback	Callback function to call when the timer expires

Returns

A pointer to the timer structure created

new_timer_context()

timer_link_t * new_timer_context	(	int	ticks,
		int	flags,
		timer_callback2_t	callback,
		void *	ctx
	)

Create a new timer with context and add to list.

If you don't need the context, consider using new_timer instead.

Parameters

[in]	ticks	Number of ticks before the timer should fire
[in]	flags	Timer flags. See TF_ONE_SHOT, TF_CONTINUOUS and TF_DISABLED
[in]	callback	Callback function to call when the timer expires
[in]	ctx	Opaque pointer to pass as an argument to callback

Returns

A pointer to the timer structure created

start_timer()

void start_timer	(	timer_link_t *	timer,
		int	ticks,
		int	flags,
		timer_callback1_t	callback
	)

Start a timer (not currently in the list)

If you need to associate some data with the timer, consider using start_timer_context to include a pointer in the callback.

Parameters

[in]	timer	Pointer to timer structure to reinsert and start
[in]	ticks	Number of ticks before the timer should fire
[in]	flags	Timer flags. See TF_ONE_SHOT, TF_CONTINUOUS, and TF_DISABLED
[in]	callback	Callback function to call when the timer expires

start_timer_context()

void start_timer_context	(	timer_link_t *	timer,
		int	ticks,
		int	flags,
		timer_callback2_t	callback,
		void *	ctx
	)

Start a timer (not currently in the list) with context.

If you don't need the context, consider using start_timer instead.

Parameters

[in]	timer	Pointer to timer structure to reinsert and start
[in]	ticks	Number of ticks before the timer should fire
[in]	flags	Timer flags. See TF_ONE_SHOT, TF_CONTINUOUS, and TF_DISABLED
[in]	callback	Callback function to call when the timer expires
[in]	ctx	Opaque pointer to pass as an argument to callback

restart_timer()

void restart_timer

(

timer_link_t *

timer

)

Reset a timer and add to list.

Parameters

[in]

timer

Pointer to timer structure to reinsert and start

stop_timer()

void stop_timer

(

timer_link_t *

timer

)

Stop a timer and remove it from the list.

Note

This function does not free a timer structure, use delete_timer to do this.

It is safe to call this function from a timer callback, including to stop a timer from its own callback.

Parameters

[in]

timer

Timer structure to stop and remove

delete_timer()

void delete_timer

(

timer_link_t *

timer

)

Remove a timer from the list and delete it.

Note

It is not safe to call this function from a timer callback.

Parameters

[in]

timer

Timer structure to stop, remove and free

timer_close()

void timer_close

(

void

)

Free and close the timer subsystem.

This function will ensure all recurring timers are deleted from the list before closing. One-shot timers that have expired will need to be manually deleted with delete_timer.

The timer subsystem tracks the number of times timer_init is called and will only close the subsystem if timer_close is called the same number of times.

timer_ticks()

long long timer_ticks

(

void

)

Return total ticks since timer was initialized, as a 64-bit counter.

Returns

Then number of ticks since the timer was initialized