High-resolution timer with callouts and timekeeping. More...

#include <px4_time.h>
#include <px4_posix.h>
#include <px4_defines.h>
#include <px4_workqueue.h>
#include <px4_tasks.h>
#include <drivers/drv_hrt.h>
#include <semaphore.h>
#include <time.h>
#include <string.h>
#include <errno.h>
#include "hrt_work.h"

Functions
hrt_abstime	hrt_absolute_time_offset ()

__EXPORT hrt_abstime	hrt_reset ()

uint64_t	hrt_system_time ()

hrt_abstime	hrt_absolute_time ()
	Get absolute time in [us] (does not wrap).

hrt_abstime	ts_to_abstime (const struct timespec *ts)
	Convert a timespec to absolute time.

hrt_abstime	hrt_elapsed_time_atomic (const volatile hrt_abstime *then)
	Compute the delta between a timestamp taken in the past and now. More...

hrt_abstime	hrt_store_absolute_time (volatile hrt_abstime *now)
	Store the absolute time in an interrupt-safe fashion. More...

bool	hrt_called (struct hrt_call *entry)
	If this returns true, the entry has been invoked and removed from the callout list, or it has never been entered. More...

void	hrt_cancel (struct hrt_call *entry)
	Remove the entry from the callout list.

void	hrt_call_init (struct hrt_call *entry)
	Initialise a hrt_call structure.

void	hrt_call_delay (struct hrt_call *entry, hrt_abstime delay)

void	hrt_init ()

void	hrt_call_after (struct hrt_call entry, hrt_abstime delay, hrt_callout callout, void arg)
	Call callout(arg) after delay has elapsed. More...

void	hrt_call_every (struct hrt_call entry, hrt_abstime delay, hrt_abstime interval, hrt_callout callout, void arg)
	Call callout(arg) after delay, and then after every interval. More...

void	hrt_call_at (struct hrt_call entry, hrt_abstime calltime, hrt_callout callout, void arg)
	Call callout(arg) at absolute time calltime.

void	abstime_to_ts (struct timespec *ts, hrt_abstime abstime)
	Convert absolute time to a timespec.

int	px4_clock_gettime (clockid_t clk_id, struct timespec *tp)

Detailed Description

High-resolution timer with callouts and timekeeping.

Function Documentation

§ hrt_call_after()

void hrt_call_after	(	struct hrt_call *	entry,
		hrt_abstime	delay,
		hrt_callout	callout,
		void *	arg
	)

Call callout(arg) after delay has elapsed.

If callout is NULL, this can be used to implement a timeout by testing the call with hrt_called().

§ hrt_call_every()

void hrt_call_every	(	struct hrt_call *	entry,
		hrt_abstime	delay,
		hrt_abstime	interval,
		hrt_callout	callout,
		void *	arg
	)

Call callout(arg) after delay, and then after every interval.

Note thet the interval is timed between scheduled, not actual, call times, so the call rate may jitter but should not drift.

§ hrt_called()

bool hrt_called ( struct hrt_call * entry )

If this returns true, the entry has been invoked and removed from the callout list, or it has never been entered.

Always returns false for repeating callouts.

§ hrt_elapsed_time_atomic()

hrt_abstime hrt_elapsed_time_atomic ( const volatile hrt_abstime * then )

Compute the delta between a timestamp taken in the past and now.

This function is safe to use even if the timestamp is updated by an interrupt during execution.

§ hrt_store_absolute_time()

hrt_abstime hrt_store_absolute_time ( volatile hrt_abstime * now )

Store the absolute time in an interrupt-safe fashion.

This function ensures that the timestamp cannot be seen half-written by an interrupt handler.