Date and Time reset at power off/on

[JoDr_3827906]

I lose my date time when VDD power lost.  We do have a battery connected to VBAT. 

I think we are missing some configuration for enabling battery back up.

We are doing the following:

[..] To enable access to the RTC Domain and RTC registers, proceed as follows:

   Enable the Power Controller (PWR) APB1 interface clock using the

       RCC_APB1PeriphClockCmd() function.

   Enable access to RTC domain using the PWR_BackupAccessCmd() function.

   Select the RTC clock source using the RCC_RTCCLKConfig() function.

   Enable RTC Clock using the RCC_RTCCLKCmd() function.

Is there more we need to do?

Thanks!