m29dw256g Numonyx, m29dw256g Datasheet - Page 43

• Manufacturer Part Number: m29dw256g
• Description: 256-mbit X16, Multiple Bank, Page, Dual Boot 3 V Supply Flash Memory
• Manufacturer: Numonyx

6.4.5
6.4.6
NVPB lock bit command set
Enter NVPB Lock Bit Command Set command
Three bus write cycles are required to issue the Enter NVPB Lock Bit Command Set
command. Once the command has been issued, the only commands allowing to set the
NVPB lock bit and the Exit Protection Command Set can be issued to the device. Any other
command is ignored. See
NVPB Lock Bit Program command
This command is used to set the NVPB lock bit to ‘0’ thus locking the NVPBs, and
preventing them from being modified.
Read NVPB Lock Bit Status command
This command is used to read the status of the NVPB lock bit.
Password protection mode command set
The device accepts the commands belonging to the Password protection mode commands
set if and only if the Password protection mode lock bit (DQ2) has been set to '0', (see
section
commands are ignored.
Enter Password Protection Command Set command
Three bus write cycles are required to issue the Enter Password Protection Command Set
command. Once the command has been issued, only the commands related to the
password protection mode and the Exit Protection Command Set can be issued to the
device. Any other command is ignored.
Password Program command
The Password Program command is used to program the 64-bit password used in the
password protection mode.
To program the 64-bit password, the complete command sequence must be entered four
times at four consecutive addresses selected by A1-A0. The Password Program command
is a special kind of Program command and must be used according to all the Program
command timings. The result from this command can be verified by checking the status
register.
The password can be checked by issuing a Password Read command.
Once password program operation has completed, an Exit Protection Command Set
command must be issued to return the device to read mode. The password protection mode
can then be selected.
By default, all password bits are set to ‘1’.
Password Read command
The Password Read command is used to verify the password used in password protection
mode.
To verify the 64-bit password, the complete command sequence must be entered four times
at four consecutive addresses selected by A1-A0.
Section 6.4.6: Password protection mode command
Section 5.2.2: Non-volatile protection bit lock
set) otherwise the password
bit.
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