Mbed & STM32F401re and RTC Accuracy

i need your help!
I have one costumised embedded board with STM32F401re MCU and 32.768 kHz external oscilator.
The problem is, i have very bad accuracy of the rtc clock - ~ 20 min / 8 month.

How it is possible that the accuracy is so bad?

Thanks in advance.

Sh. Hasani

Hi Shpejtim,

This is really a question for ST Microelectronics. You’ll have to pull down the datasheet for this device and check the accuracy of the RTC. We suggest also consulting the Reference Manual for this device family and reading the section on RTC Calibration. In fact, we just noticed ST Application Note 4759 which is focused on the RTC and covers calibration.

If you have further questions on the subject you will get better traction taking them to the ST community portal:

Ralph, Team Mbed