19.6.3.2 Automatic Battery Backup Power Switch

The supply of the backup domain can be switched automatically to VBAT supply pin by the Battery Backup Power Switch when the BOD33 detects that the VDD supply is below the VDD threshold level (BOD33.LEVEL). It is switched back to VDD supply pin when the BOD33 detects that VDD is above the VDD threshold level (BOD33.LEVEL).

To enable this feature, the following configuration is required: BOD33.ACTION=BKUP.