timer-irq.c

typedef enum _timer_mode_t {
    ONE_SHOT = 0,
    PERIODIC = 1,
} timer_mode_t;

typedef struct _machine_timer_obj_t {
    mp_obj_base_t base;
    uint32_t id;
    uint32_t period;
    timer_mode_t mode;
    mp_obj_t callback;
} machine_timer_obj_t;

static machine_timer_obj_t timer_root;

#define SYST_NUM (3)

void __attribute__((interrupt("IRQ"))) irq_timer(void) {
    if (IRQ_PEND1 & IRQ_SYSTIMER(SYST_NUM)) {
        if (timer_root.callback) {
            mp_sched_schedule(timer_root.callback, &timer_root);
        }
        if (timer_root.mode == PERIODIC) {
            systimer->C[SYST_NUM] += timer_root.period;
        } else {
            timer_disable();
        }
        systimer->CS |= (1 << SYST_NUM);
    }
}