13.11.6.3.4.1 Entering Battery Backup Mode

Entering backup mode can be triggered by either:

• Wait-for-interrupt (WFI) instruction.
• Automatic Power Switch (BBPS.CONF=APWS). When the Automatic Power Switch detects loss of Main Power, the Backup Domain will be powered by battery and the device will enter the backup mode.
• BOD33 detection: When the BOD33 detects loss of Main Power, the Backup Domain will be powered by battery and the device will enter the backup mode. For this trigger, the following register configuration is required: BOD33.ACTION=BKUP, BOD33.VMON=VDD, and BBPS.CONF=BOD33.