12.3.7 Protection Against Spurious Write

There are conditions when the user may not want to write to the Data EEPROM Memory. To protect against spurious EEPROM writes, various mechanisms have been implemented. On power-up, the WREN bit is cleared. In addition, writes to the EEPROM are blocked during the Power-up Timer period (T_PWRT).

The unlock sequence and the WREN bit together help prevent an accidental write during brown-out, power glitch or software malfunction.