M29DW128F datasheet(38/93 Pages) STMICROELECTRONICS

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6 Command Interface

M29DW128F

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the Read mode where commands issued to the Boot Block Address space will address the

Boot Blocks.

Note that when the device is in the Extended Block mode, the VPP/WP pin cannot be used for

fast programming and the Unlock Bypass mode is not available.

The Extended Block cannot be erased, and can be treated as one-time programmable (OTP)

memory. In Extended Block mode only array cell locations (Bank A) with the same addresses

as the Extended Block are not accessible. In Extended Block mode dual operations are allowed

and the Extended Block physically belongs to Bank A.

In Extended Block mode, Erase, Chip Erase, Erase Suspend and Erase resume commands are

not allowed.

To exit from the Extended Block mode the Exit Extended Block command must be issued.

The Extended Block can be protected by setting the Extended Block Protection Bit to ‘1’;

however once protected the protection cannot be undone.

6.3.2

Exit Extended Block command

The Exit Extended Block command is used to exit from the Extended Block mode and return

the device to Read mode. Four Bus Write operations are required to issue the command.

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.

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