A ds3231 library for the STM32 Blue Pill

[STM32ardui]

@STM32ardui I think sometimes observations and sheer luck (relatively unchanged environment factors e.g. constant temperature) could contribute to a higher observed accuracy.

May be.
If DS3231 is n x 0,1 ppm too fast or too slow, you can have luck to adjust it to nearly zero.

But this is only valid for 25 °C. At 70 °C LSB is equal to 0,4 ppm. No values for temperatures between.
And the crystal inside may have an aging, so after one year there is another error source to compensate.

For real accurate time keeping, I'd guess regular time sync e.g. NTP or GPS would be necessary.

DCF77 is only 50 km away from my home.