The Reset Controller (RSTCTRL) is always enabled, but some of the Reset sources must be enabled (either by fuses or by software) before they can request a Reset.

After any Reset, the Reset source that caused the Reset is found in the Reset Flag register (RSTCTRL.RSTFR).

After a Power-On Reset, only the POR flag will be set.

The flags are kept until they are cleared by writing a '1' to them.

During a Power-On Reset, all registers that are loaded from fuses are reloaded.