STM32F207 RTC Calibration

[Nimit Vachhani]

Greetings Everybody,

I have Nucleo-F207ZG board. I want to try RTC feature of this STM32. In past i did try using RTC but after some days the time used to drift and it was like 4 seconds ahead than actual time after on week and after 1 month time was ahead like almost 15 seconds. 

If you have any step by step procedure of RTC smooth digital smooth calibration then please share. I have gone through various application notes but i am getting more confused... 

Please help me.

[Peter BENSCH]

Have you seen this Knowledge Base article?

Regards
/Peter

[mƎALLEm]

Hello,

I think this application note AN2604 "STM32F101xx and STM32F103xx RTC calibration" can help you.

See also: How to calibrate the STM32's real-time clock (RTC)

[TDK]

15 seconds in 1 month is an error of 5.7 ppm. That's well within the expected tolerance of most crystals.

The calibration has a resolution of about 1 ppm. So while you can calibrate it, be realistic with your ultimate expectations on accuracy. Temperature variations will cause the largest error.