11.3.2.3.8 Chip Erase Command

The Chip Erase (CHER) command erases the Flash and the EEPROM. The EEPROM is unaltered if the EEPROM Save During Chip Erase (EESAVE) fuse in FUSE.SYSCFG0 is set.

If the device is locked, the EEPROM is always erased by a chip erase regardless of the EESAVE bit. The read/write protection (BOOTRP, APPCODEWP, APPDATAWP) bits in NVMCTRL.CTRLB do not prevent the operation. All Flash and EEPROM bytes will read back 0xFF after this command.

This command can only be started from the UPDI.