We are using STM32 internal RTC with 32.768 KHz LSI RC clock. We are observing very large drift in time(Approx 3min lag in 1 Hour).
We have gone through the RTC calibration application note.But that requires manual measurement of LSI clock deviation or external source to calculate LSI deviation.
Is there any other way to auto-calibrate RTC?
How much accuracy we can achieve with calibration?
Please suggest if any existing example code is there for STM32F4 RTC calibration.