Initialization

Before a Brown-Out Detector (BODVDD) is enabled, it must be configured, as outlined by the following:

Set the BOD threshold level (BODVDD.LEVEL)
Set the configuration in active, standby (BODVDD.ACTCDG, BODVDD.STDBYCFG)
Set the prescaling value if the BOD will run in sampling mode (BODVDD.PSEL)
Set the action and hysteresis (BODVDD.ACTION and BODVDD.HYST)

The BODVDD register is Enable-Protected, meaning that they can only be written when the respective BOD is disabled (BODVDD.ENABLE=0 and SYNCBUSY.BODVDDEN=0). As long as the Enable bit is '1', any writes to Enable-Protected registers will be discarded, and an APB error will be generated. The Enable bits are not Enable-Protected.