MX29GL320EHT2I-70G Datasheet, PDF (35/77 Pages) Macronix International – DATASHEET

MX29GL320E T/B
MX29GL320E H/L
3. Solid Protection Bit Lock Bit
The Solid Protection Bit Lock Bit (SPBLK) is assigned to control all SPB status. It is an unique and volatile. When
SPBLK=0 (set), all SPBs are locked and can not be changed. When SPBLK=1 (cleared), all SPBs are allowed to
be changed.
There is no software command sequence requested to unlock this bit, unless the device is in the password
protection mode. To clear the SPB Lock Bit, just execute a hardware reset or a power-up cycle. In order to
prevent modification, the SPB Lock Bit must be set (SPBLK=0) after all SPBs are set to desired status.
4. Password Protection Method
The security level of Password Protection Method is higher than the Solid protection mode. The 64 bit password
is requested before modifying SPB lock bit status. When device is under password protection mode, the SPB
lock bit is set as “0”, after a power-up cycle or Reset Command.
A correct password is required for password Unlock command to unlock the SPB lock bit. Await 2us is necessary
to unlock the device after a valid password is given. After that, the SPB bits are allowed to be changed. The
Password Unlock command is issued slower than 2 μs every time, to prevent hacker from trying all the 64-bit
password combinations.
There are a few steps to start password protection mode:
(1). Set a 64-bit password for verification before entering the password protection mode. This verification is only
allowed in password programming.
(2). Set the Password Protection Mode Lock Bit to”0” to activate the password protection mode.
Once the password protection mode lock bit is programmed, the programmed Q2 bit can not be erased any more
and the device will remain permanently in password protection mode. The previous set 64-bit password can not
be retrieved or programmed. All the commands to the password-protected address will also be disabled.
All the combinations of the 64-bit password can be used as a password, and programming the password does
not require special address. The password is defaulted to be all “1” when shipped from the factory. Under
password program command, only "0" can be programmed. In order to prevent access, the Password Mode
Locking Bit must be set after the Password is programmed and verified. To set the Password Mode Lock Bit will
prevent this 64-bits password to be read on the data bus. Any modification is impossible then, and the password
can not be checked anymore after the Password Mode Lock Bit is set.
P/N:PM1509
REV. 1.5, OCT. 21, 2015
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