Having problems with DS1307 RTC ... #2

Thread Starter


Joined May 1, 2021
I brought a DS1307 chip incuding battery and crystal. I made the circuit in a breadboard and wired everything with arduino. It turns out that I can set the time, but the clock does not run at all. I have disconnected Vcc and the chip still holds time, but the clock does not run.

What is the problem?

I want to mention that I did not buy a module, beacuse I could build it myself.

View attachment 133938
i had same problem, i connected 22pf ceramic capacitor between pin 2 and gnd it worked, but i have problem the clock leading few seconds per day

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Joined Aug 7, 2020
Because it's on a breadboard I bet there's too much capacitance on the crystal. Dallas's RTC ICs have load capacitance built in, and adding any more stops it working.
(I know because I once misread the datasheet and added 15pF to ground either side of the crystal like one would on a microprocessor crystal, and it wouldn't oscillate)


Joined Apr 24, 2011
Using an RTC with an external crystal is so 2010-ish.

Modern devices have the crystal integrated inside the package so they can monitor it's temperature and maintain seconds per year accuracy.

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