Millisecond interval event timers

Provides timers for events up to $2^{32}$ milliseconds in the future. More...

Detailed Description

Provides timers for events up to $2^{32}$ milliseconds in the future.

Note

Experimental and likely to replaced with unified timer API

RIOT's main timer subsystem is ztimer but compared to ztimer, evtimer offers:

• only relative 32-bit millisecond timer values Events can be scheduled with a relative offset of up to ~49.7 days in the future. **For time-critical stuff, use ztimer!**
• more flexible, "intrusive" timer type evtimer_event_t only contains the necessary fields, which can be extended as needed, and handlers define actions taken on timer triggers. Check out evtimer_msg_event_t as example.
• when a number of timeouts with the same callback function need to be scheduled, evtimer is using less RAM (due to storing the callback function only once), while each ztimer has a function pointer for the callback.

Files
file	evtimer.h
	evtimer API definitions
file	evtimer_mbox.h
	Message box based evtimer event.
file	evtimer_msg.h
	IPC-based evtimer definitions.

Data Structures
struct	evtimer_event
	Generic event. More...
struct	evtimer_t
	Event timer. More...
struct	evtimer_mbox_event_t
	Message box event definition. More...
struct	evtimer_msg_event_t
	IPC-message event. More...

Typedefs
typedef struct evtimer_event	evtimer_event_t
	Generic event.
typedef void(*	evtimer_callback_t) (evtimer_event_t *event)
	Event timer callback type.
typedef evtimer_t	evtimer_msg_t
	IPC-message event timer.

Functions
void	evtimer_init (evtimer_t *evtimer, evtimer_callback_t handler)
	Initializes an event timer.
void	evtimer_add (evtimer_t *evtimer, evtimer_event_t *event)
	Adds event to an event timer.
void	evtimer_del (evtimer_t *evtimer, evtimer_event_t *event)
	Removes an event from an event timer.
void	evtimer_print (const evtimer_t *evtimer)
	Print overview of current state of an event timer.
static uint32_t	evtimer_now_msec (void)
	Return the current system time in msec.
static void	evtimer_add_mbox (evtimer_t *evtimer, evtimer_mbox_event_t *event, mbox_t *mbox)
	Adds mbox event to an event timer.
static void	_evtimer_mbox_handler (evtimer_event_t *event)
	Event handler for mbox events.
static void	evtimer_init_mbox (evtimer_t *evtimer)
	Initializes event timer for mbox events.
static void	evtimer_add_msg (evtimer_msg_t *evtimer, evtimer_msg_event_t *event, kernel_pid_t target_pid)
	Adds event to an event timer that handles events via IPC.
static void	_evtimer_msg_handler (evtimer_event_t *event)
	Event handler for IPC messages.
static void	evtimer_init_msg (evtimer_t *evtimer)
	Initializes event timer to handle events via IPC.

Typedef Documentation

evtimer_callback_t

typedef void(* evtimer_callback_t) (evtimer_event_t *event)

Event timer callback type.

Definition at line 64 of file evtimer.h.

evtimer_msg_t

typedef evtimer_t evtimer_msg_t

IPC-message event timer.

Definition at line 34 of file evtimer_msg.h.

Function Documentation

_evtimer_mbox_handler()

static void _evtimer_mbox_handler ( evtimer_event_t *  event )

inlinestatic

Event handler for mbox events.

Precondition

event is not NULL.

Parameters

[in]

event

The event to handle

Definition at line 66 of file evtimer_mbox.h.

_evtimer_msg_handler()

static void _evtimer_msg_handler ( evtimer_event_t *  event )

inlinestatic

Event handler for IPC messages.

Parameters

[in]

event

The event to handle

Definition at line 67 of file evtimer_msg.h.

evtimer_add()

void evtimer_add	(	evtimer_t *	evtimer,
		evtimer_event_t *	event
	)

Adds event to an event timer.

Parameters

[in]	evtimer	An event timer
[in]	event	An event

evtimer_add_mbox()

static void evtimer_add_mbox ( evtimer_t *  evtimer, evtimer_mbox_event_t *  event, mbox_t *  mbox  )

inlinestatic

Adds mbox event to an event timer.

Precondition

evtimer is not NULL.

event is not NULL.

mbox is not NULL.

Parameters

[in]	evtimer	Timer to add event.
[in]	event	Event to add.
[in]	mbox	Mbox to store event->msg timer expiration.

Definition at line 50 of file evtimer_mbox.h.

evtimer_add_msg()

static void evtimer_add_msg ( evtimer_msg_t *  evtimer, evtimer_msg_event_t *  event, kernel_pid_t  target_pid  )

inlinestatic

Adds event to an event timer that handles events via IPC.

Parameters

[in]	evtimer	An event timer
[in]	event	An event
[in]	target_pid	The PID of the thread that should receive the IPC message

Definition at line 53 of file evtimer_msg.h.

evtimer_del()

void evtimer_del	(	evtimer_t *	evtimer,
		evtimer_event_t *	event
	)

Removes an event from an event timer.

Parameters

[in]	evtimer	An event timer
[in]	event	An event

evtimer_init()

void evtimer_init	(	evtimer_t *	evtimer,
		evtimer_callback_t	handler
	)

Initializes an event timer.

Warning

BEWARE! Callbacks from evtimer_init() are being executed in interrupt context. DON'T USE THIS FUNCTION unless you know exactly what that means.

Parameters

[in]	evtimer	An event timer
[in]	handler	An event handler function

evtimer_init_mbox()

static void evtimer_init_mbox ( evtimer_t *  evtimer )

inlinestatic

Initializes event timer for mbox events.

Precondition

evtimer is not NULL.

Parameters

[in]

evtimer

An event timer

Definition at line 80 of file evtimer_mbox.h.

evtimer_init_msg()

static void evtimer_init_msg ( evtimer_t *  evtimer )

inlinestatic

Initializes event timer to handle events via IPC.

Parameters

[in]

evtimer

An event timer

Definition at line 78 of file evtimer_msg.h.

evtimer_now_msec()

static uint32_t evtimer_now_msec ( void  )

inlinestatic

Return the current system time in msec.

Definition at line 115 of file evtimer.h.

evtimer_print()

void evtimer_print

(

const evtimer_t *

evtimer

)

Print overview of current state of an event timer.

Parameters

[in]

evtimer

An event timer