Event timers provides a way to generate timed events. An event timer will post an event to the process that set the timer when the event timer expires.
An event timer is declared as a struct
etimer
and all access to the event timer is made by a pointer to the declared event timer.
- See also
- Simple timer library
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Clock library (used by the timer library)
◆ data
◆ add_timer()
static void add_timer |
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struct etimer * |
timer | ) |
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static |
◆ etimer_adjust()
void etimer_adjust |
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struct etimer * |
et, |
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int |
td |
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) |
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Adjust the expiration time for an event timer.
- Parameters
-
et | A pointer to the event timer. |
td | The time difference to adjust the expiration time with. This function is used to adjust the time the event
timer will expire. It can be used to synchronize
periodic timers without the need to restart the timer
or change the timer interval.
\note This function should only be used for small
adjustments. For large adjustments use etimer_set()
instead.
\note A periodic timer will drift unless the
etimer_reset() function is used.
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- See also
- etimer_set()
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etimer_reset()
◆ etimer_expiration_time()
Get the expiration time for the event timer.
- Parameters
-
et | A pointer to the event timer |
- Returns
- The expiration time for the event timer.
This function returns the expiration time for an event timer.
◆ etimer_expired()
Check if an event timer has expired.
- Parameters
-
et | A pointer to the event timer |
- Returns
- Non-zero if the timer has expired, zero otherwise.
This function tests if an event timer has expired and
returns true or false depending on its status.
◆ etimer_next_expiration_time()
Get next event timer expiration time.
- Returns
- Next expiration time of all pending event timers. If there are no pending event timers this function returns 0.
This functions returns next expiration time of all
pending event timers.
◆ etimer_pending()
int etimer_pending |
( |
void |
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Check if there are any non-expired event timers.
- Returns
- True if there are active event timers, false if there are no active timers.
This function checks if there are any active event timers that have not expired.
◆ etimer_request_poll()
void etimer_request_poll |
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void |
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Make the event timer aware that the clock has changed.
This function is used to inform the event timer module
that the system clock has been updated. Typically, this
function would be called from the timer interrupt
handler when the clock has ticked.
◆ etimer_reset()
Reset an event timer with the same interval as was previously set.
- Parameters
-
et | A pointer to the event timer. This function resets the event timer with the same
interval that was given to the event timer with the
etimer_set() function. The start point of the interval
is the exact time that the event timer last
expired. Therefore, this function will cause the timer
to be stable over time, unlike the etimer_restart()
function.
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- See also
- etimer_restart()
◆ etimer_restart()
void etimer_restart |
( |
struct etimer * |
et | ) |
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Restart an event timer from the current point in time.
- Parameters
-
et | A pointer to the event timer. This function restarts the event timer with the same
interval that was given to the etimer_set()
function. The event timer will start at the current
time.
\note A periodic timer will drift if this function is
used to reset it. For periodic timers, use the
etimer_reset() function instead.
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- See also
- etimer_reset()
◆ etimer_set()
Set an event timer.
- Parameters
-
et | A pointer to the event timer |
interval | The interval before the timer expires. This function is used to set an event timer for a time
sometime in the future. When the event timer expires,
the event PROCESS_EVENT_TIMER will be posted to the
process that called the etimer_set() function.
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◆ etimer_start_time()
Get the start time for the event timer.
- Parameters
-
et | A pointer to the event timer |
- Returns
- The start time for the event timer.
This function returns the start time (when the timer
was last set) for an event timer.
◆ etimer_stop()
void etimer_stop |
( |
struct etimer * |
et | ) |
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Stop a pending event timer.
- Parameters
-
et | A pointer to the pending event timer. This function stops an event timer that has previously
been set with etimer_set() or etimer_reset(). After
this function has been called, the event timer will not
emit any event when it expires.
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◆ PROCESS()
◆ PROCESS_NAME()
◆ PROCESS_THREAD()
◆ update_time()
static void update_time |
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void |
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static |
◆ next_expiration
◆ timerlist