m29dw256g Numonyx, m29dw256g Datasheet - Page 39

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

6.4
6.4.1
6.4.2
Protection commands
Blocks can be protected individually against accidental program, erase operations. The
device block protection scheme is shown in
either or
The memory block and extended memory block protection is configured through the lock
register (see
The program commands referred to in the following sections must be used according to all
the Program command timings listed here:
Lock Register Command Set
The M29DW256G offers a set of commands to access the lock register and to configure and
verify its content. See the following sections in conjunction with
and
Enter Lock Register Command Set command
Three bus write cycles are required to issue the Enter Lock Register Command Set
command. Once the command has been issued, all bus read or program operations are
issued to the lock register.
An Exit Protection Command Set command must then be issued to return the device to read
mode (see
Lock Register Program and Lock Register Read command
The Lock Register Program command allows to configure the lock register. The
programmed data can then be checked by issuing a Lock Register Read command.
Extended Memory Block
The M29DW256G has one extra 128-word block (extended memory block) that can only be
accessed using the Enter Extended Memory Block command.
The extended memory block cannot be erased, and is one-time programmable (OTP)
memory.
In extended block mode, Erase, Chip Erase, Erase Suspend and Erase Resume commands
are not allowed.
To exit from the extended memory block mode the Exit Extended Memory Block command
must be issued.
Table
Figure 15.: Write enable controlled program
Figure 16.: Chip enable controlled program
Table 14
14.
Section 6.4.7: Exit Protection Command Set
Section 5.4: Lock
for a summary of the block protection commands.
register).
Figure 5: Software protection
waveforms.
waveforms,
command).
Section 5.4: Lock register
scheme. See
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