VAR-SOM-AM43 RTC
From Variscite Wiki
RTC
To set the RTC first set the date from Linux shell, type:
$ date 2013.08.27-15:43
Then set the real time clock from Linux shell, type:
$ hwclock --systohc
Power down your board wait 15 seconds and power up. Check your system with date and the time should be up to date.