256Mb, 512Mb, 1Gb, 2Gb: 3V Embedded Parallel NOR Flash
Registers
Lock Register
Table 9: Lock Register Bit Definitions
Note 1 applies to entire table
Bit Name
Settings
Description
Notes
DQ2 Password
protection
0 = Password protection
mode enabled
Places the device permanently in password protection mode.
2
mode lock bit 1 = Password protection
mode disabled (Default)
DQ1 Nonvolatile
protection
0 = Nonvolatile protection Places the device in nonvolatile protection mode with pass-
mode enabled with pass- word protection mode permanently disabled. When shipped
2
mode lock bit word protection mode
from the factory, the device will operate in nonvolatile protec-
tion mode, and the memory blocks are unprotected.
permanently disabled
1 = Nonvolatile protection
mode enabled (Default)
DQ0 Extended
memory
0 = Protected
If the device is shipped with the extended memory block un-
1 = Unprotected (Default) locked, the block can be protected by setting this bit to 0. The
extended memory block protection status can be read in auto
select mode by issuing an AUTO SELECT command.
block
protection bit
1. The lock register is a 16-bit, one-time programmable register. DQ[15:3] are reserved and
are set to a default value of 1.
Notes:
2. The password protection mode lock bit and nonvolatile protection mode lock bit cannot
both be programmed to 0. Any attempt to program one while the other is programmed
causes the operation to abort, and the device returns to read mode. The device is ship-
ped from the factory with the default setting.
Table 10: Block Protection Status
Nonvolatile
Block
Protection
Status
Protection Bit
Lock Bit1
Nonvolatile
Volatile
Protection Bit2 Protection Bit3
Block Protection Status
1
1
1
1
1
1
0
0
1
0
1
0
00h
01h
01h
01h
Block unprotected; nonvolatile protection bit changea-
ble.
Block protected by volatile protection bit; nonvolatile
protection bit changeable.
Block protected by nonvolatile protection bit; nonvola-
tile protection bit changeable.
Block protected by nonvolatile protection bit and vola-
tile protection bit; nonvolatile protection bit changea-
ble.
0
0
0
1
1
0
1
0
1
00h
01h
01h
Block unprotected; nonvolatile protection bit un-
changeable.
Block protected by volatile protection bit; nonvolatile
protection bit unchangeable.
Block protected by nonvolatile protection bit; nonvola-
tile protection bit unchangeable.
PDF: 09005aef849b4b09
m29ew_256mb_2gb.pdf - Rev. B 8/12 EN
Micron Technology, Inc. reserves the right to change products or specifications without notice.
21
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