M29W256GH7AN6E NUMONYX, M29W256GH7AN6E Datasheet - Page 24

• Manufacturer Part Number: M29W256GH7AN6E
• Description: Flash Mem Parallel 3V/3.3V 256M-Bit 32M x 8/16M x 16 70ns 56-Pin TSOP Tray
• Manufacturer: NUMONYX

Specifications of M29W256GH7AN6E

• Package: 56TSOP
• Cell Type: NOR
• Density: 256 Mb
• Architecture: Sectored
• Block Organization: Symmetrical
• Location Of Boot Block: Bottom|Top
• Typical Operating Supply Voltage: 3|3.3 V
• Sector Size: 128KByte x 256
• Timing Type: Asynchronous
• Operating Temperature: -40 to 85 °C
• Interface Type: Parallel

5.2.2
Note:
5.3
Note:
24/97
1
2
Refer to
details on the block protection mechanism, and to
volatile protection mode command set.
Non-volatile protection bit lock bit
The non-volatile protection bit lock bit (NVPB lock bit) is a global volatile bit for all blocks.
When set (programmed to ‘0’), it prevents changing the state of the NVPBs. When cleared
(programmed to ‘1’), the NVPBs can be set and reset using the NVPB Program command
and Clear all NVPBs command, respectively.
There is only one NVPB lock bit per device.
Refer to
No software command unlocks this bit unless the device is in password protection mode; it
can be cleared only by taking the device through a hardware reset or a power-up.
The NVPB lock bit must be set (programmed to ‘0’) only after all NVPBs are configured to
the desired settings.
Password protection mode
The password protection mode provides an even higher level of security than the non-
volatile protection mode by requiring a 64-bit password for unlocking the device NVPB lock
bit.
In addition to this password requirement, the NVPB lock bit is set ‘0’ after power-up and
reset to maintain the device in password protection mode. Successful execution of the
Password Unlock command by entering the correct password clears the NVPB lock bit,
allowing for block NVPBs to be modified.
If the password provided is not correct, the NVPL lock bit remains locked and the state of
the NVPBs cannot be modified.
To place the device in password protection mode, the following steps are required:
1.
2.
Refer to
There is no means to verify the password after it is set. If the password is lost after setting
the password mode lock bit, there is no way to clear the NVPB lock bit.
Prior to entering the password protection mode, it is necessary to set a 64-bit password
and to verify it (see
verification is only allowed during the password programming operation
The password protection mode is then activated by programming the password
protection mode lock bit to ‘0’. This operation is not reversible and once the bit is
programmed it cannot be erased, the device permanently remains in password
protection mode, and the 64-bit password can neither be retrieved nor reprogrammed.
Moreover, all commands to the address where the password is stored, are disabled.
Refer to
details on the block protection scheme.
Table 11: Block protection status
Section 6.4.5
Section 6.4.6
Table 11: Block protection status
for a description of the NVPB lock bit command set.
for a description of the password protection mode command set.
Password protection mode command set on page
and
and
Figure 5: Software protection scheme
Section 6.4.4
Figure 5: Software protection scheme
for a description of the non-
47). Password
for
for