JS28F256P30B95A datasheet(38/97 Pages) MICRON

38 / 97 page

P30

Datasheet

August 2008

306666-12

10.1.4

Block Lock Status

The Read Device Identifier command is used to determine a block’s lock status (see

Section 12.0, “Power and Reset Specifications” on page 50). Data bits DQ[1:0] display

the addressed block’s lock status; DQ0 is the addressed block’s lock bit, while DQ1 is

the addressed block’s lock-down bit.

10.1.5

Block Locking During Suspend

Block lock and unlock changes can be performed during an erase suspend. To change

block locking during an erase operation, first issue the Erase Suspend command.

Monitor the Status Register until SR[7] and SR[6] are set, indicating the device is

suspended and ready to accept another command.

Next, write the desired lock command sequence to a block, which changes the lock

state of that block. After completing block lock or unlock operations, resume the erase

operation using the Erase Resume command.

Note:

A Lock Block Setup command followed by any command other than Lock Block, Unlock Block,

or Lock-Down Block produces a command sequence error and set Status Register bits SR[4]

and SR[5]. If a command sequence error occurs during an erase suspend, SR[4] and SR[5]

remains set, even after the erase operation is resumed. Unless the Status Register is cleared

using the Clear Status Register command before resuming the erase operation, possible erase

errors may be masked by the command sequence error.

Figure 12: Block Locking State Diagram

[X00]

[X01]

Power-Up/Reset

Unlocked

Locked

[011]

[111]

[110]

Locked-

Down

4,5

Software

Locked

[011]

Hardware

Locked

Unlocked

WP# Hardware Control

Notes:

1. [a,b,c] represents [WP#, DQ1, DQ0]. X = Don’t Care.

2. DQ1 indicates Block Lock-Down status. DQ1 = ‘0’, Lock-Down has not been issued

to this block. DQ1 = ‘1’, Lock-Down has been issued to this block.

3. DQ0 indicates block lock status. DQ0 = ‘0’, block is unlocked. DQ0 = ‘1’, block is

locked.

4. Locked-down = Hardware + Software locked.

5. [011] states should be tracked by system software to determine difference between

Hardware Locked and Locked-Down states.

Software Block Lock (0x60/0x01) or Software Block Unlock (0x60/0xD0)

Software Block Lock-Down (0x60/0x2F)

WP# hardware control

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