Can I use only the SAMD21 mini breakout board and OLED to make a watch? Do I need to buy DS3231??

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1

I am trying to use this small board and an OLED display to show a digit format time, day, month, year, and days of week.

Do I need an extra RTC module like DS3231?

I checked the document, "The SparkFun SAMD21 Mini Breakout has been equipped with a USB interface for programming and power, surrounded with an RTC crystal, and a 600mA 3.3V regulator. "

2

You could use either :smiley:

3

The temperature compensated DS3231 would keep time more accurately, but take up space.

4

Try without the DS3231, you might find the SAMD21 alone is accurate enough for your needs.

If it’s consistently slow or fast by the same amount over time you could code your sketch to compensate for that drift. If it’s not consistent or accurate accurate enough, add the DS3231. :slight_smile: