I want to make a digital clock project, but with my own PCB design. My question is, if I use a DS3231 IC, will it know already what to do, or I have upload something in order to make the AtMega32U4 operate with it?

You do not need to upload anything to the RTC apart from setting the correct time

Using DS3231 RTC IC in projects

Railroader October 31, 2021, 10:32pm 6

No clock is fabricated being set to the current time and running from there.

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