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Problems using Backup Battery on F103C8T6 Controller

Question asked by Sierpinski.Markus on Feb 6, 2017
Latest reply on Feb 7, 2017 by waclawek.jan


I designed a circuit that contains a CR2032 Battery for backing up the RTC.
The circuit is shown below.
Without the battery the RTC is running well and an initialize of the RTC is no Problem.
After inserting the battery the controller won't startup anymore.
The program hangs while the RTC is initialize. The function is waiting that the RTC registers will be syncronized. But the RSF Bit will be never set.
If i remove the battery the RSF Bit is immediately set.
I also tried to connect VDD directly to the VBAT Pin, but that results in the same situation, the RTC is not working and the program is hanging.


Is there something that i have forgotten to do?
I already tried to searched the REF manual but without success.