File content as of revision 4:da41f0e17d5a:

#include "mbed.h"
#include "wakeup.h"
#include "rtc_api.h"
#include "mbed_mktime.h"

#define YEAR0       1900

static Semaphore sem_rtc(0, 1);

static void rtc_loop(void);
static void schedule_rtc_alarm(uint32_t secs);

void RTC_IRQHandler(void)
{
    /* Check if RTC alarm interrupt has occurred */
#if defined(TARGET_NUMAKER_PFM_NUC472)
    if (RTC->INTSTS & RTC_INTSTS_ALMIF_Msk) {
        /* Clear RTC alarm interrupt flag */
        RTC->INTSTS = RTC_INTSTS_ALMIF_Msk;

        wakeup_eventflags.set(EventFlag_Wakeup_RTC_Alarm);
    }
#else
    if (RTC_GET_ALARM_INT_FLAG()) {
        /* Clear RTC alarm interrupt flag */
        RTC_CLEAR_ALARM_INT_FLAG();

        wakeup_eventflags.set(EventFlag_Wakeup_RTC_Alarm);
    }
#endif

    /* Wake up RTC loop to schedule another RTC alarm */
    sem_rtc.release();
}

void config_rtc_wakeup(void)
{
    static Thread thread_rtc;
    
    Callback<void()> callback(&rtc_loop);
    thread_rtc.start(callback);
}

void rtc_loop(void)
{
    /* Schedule RTC alarm in 3 secs */
    schedule_rtc_alarm(3);
    
    while (true) {
        int32_t sem_tokens = sem_rtc.wait(osWaitForever);
        if (sem_tokens < 1) {
            printf("RTC Alarm fails with Semaphore.wait(): %d\n", sem_tokens);
        }
        else {
            /* Re-schedule RTC alarm in 3 secs */
            schedule_rtc_alarm(3);
        }
    }
}

void schedule_rtc_alarm(uint32_t secs)
{
    /* time() will call set_time(0) internally to set timestamp if rtc is not yet enabled, where the 0 timestamp 
     * corresponds to 00:00 hours, Jan 1, 1970 UTC. But Nuvoton mcu's rtc supports calendar since 2000 and 1970 
     * is not supported. For this test, a timestamp after 2000 is explicitly set. */ 
    {
        static bool time_inited = false;
    
        if (! time_inited) {
            time_inited = true;
        
            #define CUSTOM_TIME  1256729737
            set_time(CUSTOM_TIME);  // Set RTC time to Wed, 28 Oct 2009 11:35:37
        }
    }
    
    RTC_DisableInt(RTC_INTEN_ALMIEN_Msk);
    
    time_t t = time(NULL);
    t += secs; // Schedule RTC alarm after secs
    
    // Convert timestamp to struct tm
    struct tm timeinfo;
    if (_rtc_localtime(t, &timeinfo) == false) {
        printf("config_rtc_alarm() fails\n");
        return;
    }

    S_RTC_TIME_DATA_T rtc_datetime;
    
    // Convert struct tm to S_RTC_TIME_DATA_T
    rtc_datetime.u32Year        = timeinfo.tm_year + YEAR0;
    rtc_datetime.u32Month       = timeinfo.tm_mon + 1;
    rtc_datetime.u32Day         = timeinfo.tm_mday;
    rtc_datetime.u32DayOfWeek   = timeinfo.tm_wday;
    rtc_datetime.u32Hour        = timeinfo.tm_hour;
    rtc_datetime.u32Minute      = timeinfo.tm_min;
    rtc_datetime.u32Second      = timeinfo.tm_sec;
    rtc_datetime.u32TimeScale   = RTC_CLOCK_24;
    
    RTC_SetAlarmDateAndTime(&rtc_datetime);
    
    /* NOTE: The Mbed RTC HAL implementation of Nuvoton's targets doesn't use interrupt, so we can override vector
             handler (via NVIC_SetVector). */
    /* NOTE: The name of symbol PWRWU_IRQHandler is mangled in C++ and cannot override that in startup file in C.
     *       So the NVIC_SetVector call cannot be left out. */
    NVIC_SetVector(RTC_IRQn, (uint32_t) RTC_IRQHandler);
    NVIC_EnableIRQ(RTC_IRQn);
    /* Enable RTC alarm interrupt and wake-up function will be enabled also */
    RTC_EnableInt(RTC_INTEN_ALMIEN_Msk);
}