Include

Configuration

AO_ALARM_DELAY

#define AO_ALARM_DELAY (AO_MILLISECONDS(100))

The alarm delay is an estimate of the maximum latency of the alarm interrupt. This latency may be caused by hardware, interrupts of higher priority being served, interrupts being disabled due to critical zones, or interrupt context save and restore operations, among others. This value must be greater than zero.

Constants

AO_ALARM_UPDATE

#define AO_ALARM_UPDATE \
(                       \
    (AO_TIME_MAX)    -  \
    (AO_ALARM_DELAY) +  \
    1                   \
)

The alarm update specifies the maximum time span between subsequent alarm interrupts. It takes into account the latency of the alarm interrupt in order to not miss a count overflow.

Types

ao_alarm_t

typedef struct ao_alarm_t ao_alarm_t;

Represents an alarm.

Structs

ao_alarm_t

struct ao_alarm_t
{
    ao_proc_t             callback;
    void *                callback_parameter;
    ao_time_t             end;
    ao_alarm_queue_node_t node;
    bool                  running;
};

Functions

ao_alarm_start

ao_alarm_start_from

void ao_alarm_start     (ao_alarm_t * a, ao_time_t timeout);
void ao_alarm_start_from(ao_alarm_t * a, ao_time_t timeout, ao_time_t beginning);

Starts an alarm with a timeout and an optional beginning.

ao_alarm_stop

void ao_alarm_stop(ao_alarm_t * a);

Stops an alarm.