Reading the Flash/EEPROM and writing the page buffer is handled with normal load/store instructions. Other operations, such as writing and erasing the memory arrays, are handled by commands in the NVM.

To execute a command in the NVM:
  1. 1.Confirm that any previous operation is completed by reading the Busy (EEBUSY and FBUSY) Flags in the NVMCTRL.STATUS register.
  2. 2.Write the appropriate key to the Configuration Change Protection (CPU.CCP) register to unlock the NVM Control A (NVMCTRL.CTRLA) register.
  3. 3.Write the desired command value to the CMD bit field in the Control A (NVMCTRL.CTRLA) register within the next four instructions.