M58PR256J datasheet(63/114 Pages) STMICROELECTRONICS

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M58PR256J, M58PR512J

Block locking

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12.4

Lock-Down state

Blocks that are Locked-Down (state (0,1,x))are protected from program and erase

operations (as for Locked Blocks) but their protection status cannot be changed using

software commands alone. A Locked or Unlocked Block can be Locked-Down by issuing the

Lock-Down command. Locked-Down Blocks revert to the Locked state when the device is

reset or powered-down.

The Lock-Down function is dependent on the Write Protect, WP, input pin.

When WP=0 (VIL), the Blocks in the Lock-Down state (0,1,x) are protected from program,

erase and protection status changes.

When WP=1 (VIH) the Lock-Down function is disabled (1,1,x) and Locked-Down Blocks can

be individually unlocked to the (1,1,0) state by issuing the software command, where they

can be erased and programmed.

When the Lock-Down function is disabled (WP=1) Blocks can be locked (1,1,1) and

unlocked (1,1,0) as desired. When WP=0 Blocks that were previously Locked-Down return

to the Lock-Down state (0,1,x) regardless of any changes that were made while WP=1.

Device reset or power-down resets all Blocks, including those in Lock-Down, to the Locked

state.

12.5

Locking operations during Erase Suspend

Changes to block lock status can be performed during an erase suspend by using the

standard locking command sequences to unlock, lock or lock-down a Block. This is useful in

the case when another Block needs to be updated while an erase operation is in progress.

To change block locking during an erase operation, first write the Erase Suspend command,

then check the Status Register until it indicates that the erase operation has been

suspended. Next write the desired Lock command sequence to a Block and the lock status

will be changed. After completing any desired lock, read, or program operations, resume the

erase operation with the Erase Resume command.

If a Block is locked or locked-down during an erase suspend of the same Block, the locking

status bits will be changed immediately, but when the erase is resumed, the erase operation

will complete. Locking operations cannot be performed during a program suspend.

M58PR256J Datasheet(PDF) 63 Page - STMicroelectronics