17.3.3 Sleep Mode Operation

There are two separate fuses defining the BOD configuration in different sleep modes: One fuse defines the mode used in Active mode and Idle sleep mode (ACTIVE in FUSE.BODCFG), and is written to the ACTIVE bits in the Control A register (BOD.CTRLA). The second fuse (SLEEP in FUSE.BODCFG) selects the mode used in Standby sleep mode and Power Down sleep mode, and is loaded into the SLEEP bits in the Control A register (BOD.CTRLA).

The operating mode in Active mode and Idle sleep mode (i.e. ACTIVE in BOD.CTRLA) cannot be altered by software. The operating mode in Standby sleep mode and Power Down sleep mode can be altered by writing to the SLEEP bits in the Control A register (BOD.CTRLA).

When the device is going into Standby sleep mode or Power Down sleep mode, the BOD will change operation mode as defined by SLEEP in BOD.CTRLA. When the device is waking up from Standby or Power Down sleep mode, the BOD will operate in the mode defined by the ACTIVE bit field in BOD.CTRLA.