SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
The EEPROM can be locked at both the module level and the block level. The lock is controlled by a password that is stored in the EEPROM Password (EEPASSn) registers and can be any 32-bit to 96-bit value other than all 1s. Block 0 is the master block, the password for block 0 protects the control registers as well as all other blocks. Each block can be further protected with a password for that block.
If a password is registered for block 0, then the whole module is locked at reset. As a result, the EEBLOCK register cannot be changed from 0 until block 0 is unlocked.
A password registered with any block, including block 0, allows for protection rules that control access of that block based on whether it is locked or unlocked. Generally, the lock can be used to prevent write accesses when locked or can prevent read and write accesses when locked.
All password protected blocks are locked at reset. To unlock a block, the correct password value must be written to the EEPROM Unlock (EEUNLOCK) register by writing to it once, twice, or three times, depending on the size of the password. A block or the module can be re-locked by writing 0xFFFF.FFFF to the EEUNLOCK register because 0xFFFF.FFFF is not a valid password.