I have installed backup battery on SAMA5D3 Xplained board.
I'm using the linux system built from the linux4sam.
The RTC is working well but, there is something problem.
After charging 3 hours, I have cut the power for 2 hours.
And, the RTC is reset to initial state. So, I need to set the RTC again.
I think the Backup Mode for RTC is not working correctly.
How can I make it work in backup mode while powering off.
The commands that I used for setting RTC are following,
# date -s '2015-06-26 17:07:30'
# hwclock -w