11.3.2.3.4 EEPROM Write Mode

The EEPROM Write (EEWR) mode enables the EEPROM array for writing operations. Several writes can be done while the EEWR mode is enabled in the NVMCTRL.CTRLA register. When the EEWR mode is enabled, writes with the ST* instructions will be performed one byte at a time.

When writing the EEPROM, the CPU will continue executing code. If a new load/store operation is started before the EEPROM erase/write is completed, the CPU will be halted.

Before a write is performed to an address, its content needs to be erased.