M29DW128F datasheet(42/94 Pages) STMICROELECTRONICS

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Command interface

M29DW128F

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6.3.3

Set Extended Block Protection bit command

The Set Extended Block Protection bit command programs the Extended Block Protection

bit to ‘1’ thus preventing the second section of the Extended Block from being programmed.

A Read/Reset command must be issued to abort a Set Extended Block Protection bit

command.

Six successive steps are required to issue the Set Extended Block Protection bit command.

The command starts with two unlock cycles.

The third Bus Write cycle sets up the Set Extended Block Protection bit command.

The fourth Bus Write Cycle programs the Extended Block Protection bit to ‘1’.

The last two cycles verify the value programmed at the Extended Block Protection bit

address: if bit DQ0 of Data Inputs/Outputs is set to ’1’, it indicates that the Extended

Block Protection bit has been successfully programmed. If DQ0 is ‘0’, the Set Extended

Block Protection bit command must be issued and verified again.

6.3.4

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.

6.3.5

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:

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.

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’.

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