TikuOS: Simple. Ubiquitous. Intelligence, Everywhere.

Timers & Clock

TikuOS provides three timing primitives: the system clock (the free-running tick source), software timers (managed by a process, either event-posting or callback-driven), and the hardware timer (a single-shot, ISR-dispatched timer used when you need precise control and cannot tolerate process-dispatch latency).

Headers: kernel/timers/tiku_timer.h, kernel/timers/tiku_clock.h, kernel/timers/tiku_htimer.h.

Software Timers

Header: kernel/timers/tiku_timer.h

Unified timer supporting two modes: event (posts TIKU_EVENT_TIMER to a process) and callback (invokes a function directly). Any number of timers can be active simultaneously; they're managed as a linked list and checked each scheduler iteration.

Types

typedef void (*tiku_timer_callback_t)(void *ptr);

struct tiku_timer {
    struct tiku_timer *next;        /* Linked list pointer (internal)       */
    tiku_clock_time_t start;        /* When the timer was set               */
    tiku_clock_time_t interval;     /* Duration in clock ticks              */
    uint8_t mode;                   /* TIKU_TIMER_MODE_EVENT or _CALLBACK   */
    uint8_t active;                 /* Non-zero if in the active list       */
    struct tiku_process *p;         /* Event target or callback context     */
    tiku_timer_callback_t func;     /* Callback function (CALLBACK mode)    */
    void *ptr;                      /* User data for callback               */
};

Constants

Functions

Examples

Event timer (most common)

static struct tiku_timer my_timer;

TIKU_PROCESS_THREAD(my_proc, ev, data)
{
    TIKU_PROCESS_BEGIN();

    tiku_timer_set_event(&my_timer, TIKU_CLOCK_SECOND);

    while (1) {
        TIKU_PROCESS_WAIT_EVENT_UNTIL(ev == TIKU_EVENT_TIMER);
        /* periodic work */
        tiku_timer_reset(&my_timer);  /* drift-free */
    }

    TIKU_PROCESS_END();
}

Callback timer

static struct tiku_timer cb_timer;

static void on_timeout(void *ptr)
{
    /* runs on next scheduler pass that notices the expired timer */
}

tiku_timer_set_callback(&cb_timer, TIKU_CLOCK_SECOND * 2, on_timeout, NULL);

System Clock

Header: kernel/timers/tiku_clock.h

Free-running tick source driven by a low-frequency clock (typically ACLK from the 32 kHz crystal). Provides the time base used by all software timers.

Types

typedef unsigned short tiku_clock_time_t;

Constants and Macros

Functions

Hardware Timer

Header: kernel/timers/tiku_htimer.h

Single-shot hardware timer with ISR-context callbacks. Only one htimer can be pending at a time — setting a new one replaces any previously scheduled timer. Use this when you need microsecond-level precision or cannot tolerate the process-dispatch latency of software timers.

Types

typedef unsigned short tiku_htimer_clock_t;
typedef void (*tiku_htimer_callback_t)(struct tiku_htimer *t, void *ptr);

struct tiku_htimer {
    tiku_htimer_clock_t time;       /* Scheduled firing time (absolute)     */
    tiku_htimer_callback_t func;    /* ISR callback                         */
    void *ptr;                      /* User data for callback               */
};

Return Codes

Macros

Functions