I am currently working with an STM32U5 microcontroller and would like to request more information on the process of calibrating the RTC (Real-Time Clock). We are using an external 32.768 kHz LSE oscillator with 10pf burden capacitors, but we are observing a 6-second drift over 24 hours.
I have followed the calibration process outlined in the link below:
STM32 RTC Calibration Process[https://community.st.com/t5/stm32-mcus/how-to-calibrate-the-stm32-s-real-time-clock-rtc/ta-p/744958?search-action-id=38939113459&search-result-uid=744958].
However, I need more detailed information regarding the calibration procedure.
1. I'm not clear how to calculate the correct CALM[8:0] value for the smooth calibration register (RTC_CALR).
1. How to Verifying the RTC calibration?
2. Is it necessary to perform smooth calibration at regular intervals? If so, what are the steps to do this?
