How to set RTC secure mode STM32U5 Series

[JAltu.1]

I would like to use the WKUP 6 (RTC_WUT_S) to wake up from Standby mode. I am already using WKUP 7 with a pin so I need the RTC to be in safe mode.

What would be the best way?

[STea]

Hello @JAltu.1 ,

I don't get you exact request what do you mean by saying "RTC to be in safe mode".

are you working with trustzone enabled?
if yes then working with RTC in a safe way should be done by setting WUTSEC bit in control register 

When WUTSEC is set:
– RTC_WUTR register, plus WUTE, WUTIE and WUCKSEL control bits in the
RTC_CR, CWUTF in the RTC_SCR, WUTF in RTC_SR, and WUTMF in
RTC_SMISR can be read and written only in secure mode.
– WUTPRIV in the RTC_PRIVCFGR can be written only in secure mode
please refer to RM0456 section 63.3.4 RTC secure protection modes for more details. 
Regards

[JAltu.1]

Hi @STea ,

Trustzone is disabled. I have seen it can be enabled creating a new project.

But how can I do it in a existing project?

Regards

[STea]

Hello @JAltu.1 ,

You can't add Trustzone to an existing non-Trustzone application. you will have to start a new project with Trustzone enabled in order to have the isolation and security features that it offers with the secure and non-secure projects.

Regards