m29dw641f STMicroelectronics, m29dw641f Datasheet - Page 34

• Manufacturer Part Number: m29dw641f
• Description: 64 Mbit 4mb X16, Multiple Bank, Boot Block 3v Supply Flash Memory
• Manufacturer: STMicroelectronics

Command interface
6.3.4
6.3.5
6.3.6
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Verify Extended Block Protection bit command
The Verify Extended Block Protection bit command reads the status of the Extended Block
Protection bit on bit DQ0 of the Data Inputs/Outputs. If DQ0 is ‘1’, the second section of the
Extended Block is protected from Program Operations.
Password Program command
The Password Program command is used to program the 64-bit Password used in Password
Protection mode.
Four cycles are required to program the Password:
1.
2.
3.
To program the 64-bit Password, the complete command sequence must be entered four
times at four consecutive addresses selected by A1 to A0.
Read Operations can be used to read the Status Register during a Password Program
Operation. All other operations are forbidden.
The Password can be checked by issuing a Password Verify command.
Once Password Program Operation has completed, a Read/ Reset 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 Verify command
The Password Verify 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 to A0.
If this command is issued while the device is in Password Protection mode, it outputs ‘FFh’
and all Inputs/Outputs are high impedance.
The Password is output regardless of the bank address.
The user must issue a Read/reset command to return the device to Read mode.
Dual Operations are not allowed during a Password Verify Operation.
The first two cycles are unlock cycles.
The third cycle issues the Password Program command.
The fourth cycle inputs the 16-bit data required to program the Password.
M29DW641F