Internal RTC goes forward 3 seconds every minute

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by askar on Sat Dec 20 00:03:43 MST 2014
Hi, everybody

Could someone kindly help me about using Internal RTC in Lpc4357?
i am using a board based on Keil project and using Internal Rtc with 32khz external crystal.
when i initialize the Rtc and set it with Date and Time according to am accurate system, i
saw that its time goes forward 3 seconds after every minute!!!.
I think there must be malfunction in somewhere maybe in my board or software.
and it will be very strange if the problem  is from Lpc4357.
The Calibration is disabled in Rtc. I compared the number of SysTicks between each minute
and for 10 minutes in successive, there were numbers such as 61000,60500,59000,58000,57800,57400,57200,56800,58000,
any help is appreciated in advance.

Best Regards,