Diffrence between RTC with DS1307 and RTC with Microcontroller Timer[Sleepm mode]

[ismu]

I am already designed Cloack by using PIC16F72 , but here am not using RTC chip ,instaed of that am using 32.768Khz X-tell to the Timer[Which will work on sleep] and when power failure happend then Chip[ will go to Sleep mode , But problem is After one month Time variation is there [2min] . So if am using DS1307 RTC chip , Can i remove this error? if yes how its happening? , because same X- tell is using in both designing.

 

[kalbun]

The time difference may have a few causes, but I suspect the problem is the crystal. Check the characteristics of your component and maybe select a better one.

DS1307 don't measure the time more precisely, but has other interesting features, like a full date/time calendar and ultra-low consumption.