M58LR128KB855 datasheet(29/110 Pages) NUMONYX

29 / 110 page

M58LR128KT, M58LR128KB, M58LR256KT, M58LR256KB

Command interface

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4.16

Block Unlock command

The Block Unlock command unlocks a block, allowing the block to be programmed or

erased.

Two bus write cycles are required to issue the Block Unlock command:

●

The first bus cycle sets up the Block Unlock command.

●

The second bus write cycle latches the block address and unlocks the block.

The lock status can be monitored for each block using the Read Electronic Signature

command. Table 17 shows the protection status after issuing a Block Unlock command.

Refer to Section 9: Block locking for a detailed explanation and Appendix C, Figure 24:

Locking operations flowchart and pseudocode for a flowchart for using the Block Unlock

command.

4.17

Block Lock-Down command

The Block Lock-Down command is used to lock down a locked or unlocked block.

A locked-down block cannot be programmed or erased. The lock status of a locked-down

block cannot be changed when WP is low, VIL. When WP is high, VIH, the lock-down function

is disabled and the locked blocks can be individually unlocked by the Block Unlock

command.

Two bus write cycles are required to issue the Block Lock-Down command:

●

The first bus cycle sets up the Block Lock-Down command.

●

The second bus write cycle latches the block address and locks down the block.

The lock status can be monitored for each block using the Read Electronic Signature

command.

Locked-down blocks revert to the locked (and not locked-down) state when the device is

reset on power-down. Table 17 shows the lock status after issuing a Block Lock-Down

command.

Refer to Section 9: Block locking for a detailed explanation and Appendix C, Figure 24:

Locking operations flowchart and pseudocode for a flowchart for using the Lock-Down

command.

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