Real Time Clock

I have a routine for RTC PIC18F24J11. I think the internal RTC is the same in 65K22.

For Write RTC
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I have been doing some playing with your PC timesetter and what and excellent little program it is.
I have got it working for the PCF8563 and the DS1307 RTC by just highlighting a couple of lines in the code with added temperature measurement.
I've tested both RTC'S over a week for each one and everyting seems to be working well, Well apart from one little bug which is do to with the temperature reading when it first starts up for the first minute it reads high on display but after that is works as it should, I'm looking into this should be easy to fix.
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There are occasions when you need to calculate the number of days between two dates. This on first thought is a complex task, what with all those variable days in a month, and leap years..
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In response to a Request on the forum I rewrote this bit of a larger lump of code to Display the time. This uses the DS1307 ...

In basic code i am using shin & shout commands with DS1307. If you want to use DS1307 RTC in your project. Simple cut ...