My boards use PowerDown & RTC function on ADuC848.
RTC is configured every 30 minute interrupt.
My boards outputs the value measured after RTC Wake up in every 30 minutes, and repeat mode to enter into PowerDown.
By the way, the error of the time which is output every 30 minutes.
I found symptoms reduced RTC time by about 0.2seconds when the output log, like <output log>
<output log> hour: minute : second
01:00:00 1000 ppm
01:30:00 1000 ppm
02:00:00 1000 ppm
02:30:00 1000 ppm
02:59:59 1000 ppm <1 second reduced>.
03:29:59 1000 ppm
03:59:59 1000 ppm
04:29:59 1000 ppm
04:59:58 1000 ppm <1 second reduced>.
05:29:58 1000 ppm
05:59:58 1000 ppm
06:29:58 1000 ppm
Why wonder whether it is time for each one to four times to output that is not exactly short.
Is due to difference speed of measure on mcu after wake up by RTC(interrupt)?