how to store rtc time in lpc 2148 if power down?

[atulclassesbalt]

I am using lpc 2148 arm7 board from nxp. I have used your example for rtc clock. It is working well but when I switches off the power of the board and again switches on the board the current time is not shown. it is not storing. as there is 3.2 volt on 49 pin of ic. why?

[CarlosCasillas]

Hi Atul,

Have you ensured that your software is not initializing the RTC registers (so, stored values are overwritten)?

Additionally, you could take a look at the following links:

https://www.embeddedrelated.com/showthread/lpc2000/38240-1.php

https://www.lpcware.com/content/forum/rtc-battery-backup

You could also take a look at section 18.5 “RTC usage notes” of the LPC2148 User Manual.

Hope this will be useful for you.
Best regards!
/Carlos
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