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Question, i.MX28 RTC

Question asked by AVNET JAPAN FAE (team share account) on Mar 29, 2016
Latest reply on Apr 11, 2016 by AVNET JAPAN FAE (team share account)

Dear team,


I would like to ask about RTC inside of i.MX28.

The issue is seen on my customer’s lab.

The issue is RTC gains 50 seconds per 7 hours.

The issue occurs on the customer’s board and EVK as well.

They use LinuxBSP, L2.6.35_1.1.0.

The source clock of RTC is 32.768KHz crystal.

The procedure to see the RTC is as below.

- Right after Boot-up,

     Set-up system clock by ‘date’ command.

     Copy the date to RTC by ‘hwclock –w’ command.

- Left for 7 hours.

- Get system clock by ‘date’ command.

- Get RTC by ‘hwclock’ command.


As the result,

The system clock seems to be right, but RTC gains 50 seconds.

Do you have any ideas on the cause of this phenomenon?