In fact, the time drift of the RTC is determined by the temperature drift curve of the external crystal. To fundamentally solve this problem, RTC time compensation needs to be performed according to the temperature drift curve of the external 32.768K crystal. Therefore, the best way is to ask the crystal manufacturer if there is a corresponding plan. For example, if you use EPSON crystals, you need to contact EPSON.
Hope the information is helpful to you.
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