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STM32F051 LSE Clock accuracy

Question asked by Sylvain.Derouville on May 6, 2014
Latest reply on May 27, 2014 by Sylvain.Derouville
hello,

I am in the development of a new application with a STM32F051R8.
I have a big problem with the accuracy of the RTC:

I used both the quartz advocate in the note AN2867 application.

I initialize the RTC well with clock LSE I check the integrity of the signal source to the oscilloscope, however I see some burst even changing repeatedly torque quartz / capacitor

I have the same problem on the prototype board made for our machine on the evaluation board is why I excluded a problem of PCB design

After 24 hours I observed a deviation which varies from 60 to 90 seconds.

This deviation is even more important if I use the timer 2 to generate an interrupt every 0.1 ms.

I do not see what can interfere with the oscillation of the quartz or registers of the RTC, did you meet with a similar case?

Thank you for your help.

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