31.2.22.3 Power On Reset (POR)

A Power On Reset (POR) causes immediate termination of any FCW operation. A POR is a full and hard reset of all states of the FCW and therefore no error flags originating from a prior operation survive the reset.

Several SFR bits reset by POR survive a BOR or user reset (WDT Reset, RESET pin, GCLK.CTRLA.SWRST, etc). Doing so allows NVM operations to report errors due to reset aborts. This also prevents values like address from changing when cleaning up an aborted operation.