13.11.6.5.1 Initialization

Before a Brown-Out Detector (BOD33) is enabled, it must be configured, as outlined by the following:
  • Set the BOD threshold level (BOD33.LEVEL)
  • Set the configuration in Active, Standby, Backup modes (BOD33.ACTCDG, BOD33.STDBYCFG, BODVDD.BKUP)
  • Set the prescaling value if the BOD will run in sampling mode (BOD33.PSEL)
  • Set the action and hysteresis (BOD33.ACTION and BOD33.HYST)

The BOD33 register is Enable-Protected, meaning that it can only be written when the BOD is disabled (BOD33.ENABLE = 0 and SYNCBUSY.BOD33EN = 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.