help needed ds3231 RTC chip

[sohel]

Dear all,

i am facing problem with ds3231 chip, after 24 hours elapsed its show 1 sec fast, i am comparing with my pc clock.

Thanks

[Parmin]

A few things come to mind

for 1:86400 errors,
- you could have inadvertently set the aging offset, or temperature register, these may change the crystal timing.
- your computer clock might be wrong,
- the reset of the clock might "just" off the turn of the second mark, and thus it "looks" like there are discrepancy.

[sohel]

thanks

good point.
"you could have inadvertently set the aging offset, or temperature register, these may change the crystal timing."
let me check my code.

[jumulab]

About the RTC / time compare against the PC clock, remember the PC RTC hardware normally have not a good
behaviour in precission terms.
To make a good check, first, syncronyze the PC time in a www based NIST timebase.
Other possible cause of inaccuracy are the induced noise into thre RTC chip.
I am using a good RTC for our product ( the NXP PCF2129A , a +/- 3pp part) and some time we have
obtained deviations of more than 1s/day ( very poorly).
Steps: check with other part, make the elapsed time for check more bigger, or try if the device
have the facility to measure the output ( or derived division) of their time base (32.768 kHz).
In some cases, the acces code writed is the cause of malfunction.