DS1307 RTC stops incrementing after a random while

[adnan_e94]

Hello,

I'm an engineering student and im making this project just for education purpose, I'm using:
-PIC 16F877A with 10 Mhz quartz
-DS1307 with 32.75 kHz crystal

The problem is that after some time (random, sometimes 10 minutes, sometimes 10 days) the DS1307 just stops incrementing the time. BUT after I "reprogram" the DS1307 (set the time values) from the PIC via I2C, it just starts to work again counting from the newly set date. Any ideas what could be the issue here?

The DS1307 DOES have a new battery attached to VBAT, and everything works flawless since the PIC reads the values the whole time perfectly (in my program i read the values every ~1 minute)

edit1: and yes, i tried another DS1307, still same issue.

 

[jayanth.devarayanadurga]

Try reading time every second but display once a minute.

 

[adnan_e94]

I tried reading every 500 ms to show the seconds as well, but decided to show less info and didnt need to read the value so often, but yea even after 2 hours the time is frozen until i do the trick with reprogramming the time from the pic.

I tried to read, then write what i read, to have the pic to program the DS1307 over and over again, but no luck.

 

[shamikrudra]

Check the RTC crystal, solder joins of crystal, is it in breadboard??
Have you place an 100nf cap between vcc and gnd of RTC.
do this simple things and report