M36WT864 Ver la hoja de datos (PDF) - STMicroelectronics

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M36WT864

64 Mbit (4Mb x16, Multiple Bank, Burst) Flash Memory and 8 Mbit (512K x16) SRAM, Multiple Memory Product

STMicroelectronics 

M36WT864TF, M36WT864BF

The Block Lock bits are volatile, once set they re-

main set until a hardware reset or power-down/

power-up. They are cleared by a Block Unlock

command. Refer to the section, Block Locking, for

a detailed explanation. See Appendix C, Figure

34, Locking Operations Flowchart and Pseudo

Code, for a flowchart for using the Lock command.

Block Unlock Command

The Block Unlock command is used to unlock a

block, allowing the block to be programmed or

erased. Two Bus Write cycles are required to is-

sue the Block Unlock command.

s The first bus cycle sets up the Block Unlock

command.

s The second Bus Write cycle latches the block

address.

The lock status can be monitored for each block

using the Read Electronic Signature command.

Table 13 shows the protection status after issuing

a Block Unlock command. Refer to the section,

Block Locking, for a detailed explanation and Ap-

pendix C, Figure 34, Locking Operations Flow-

chart and Pseudo Code, for a flowchart for using

the Unlock command.

Block Lock-Down Command

A locked or unlocked block can be locked-down by

issuing the Block Lock-Down command. A locked-

down block cannot be programmed or erased, or

have its protection status changed when WP is

low, VIL. When WP is high, VIH, the Lock-Down

function is disabled and the locked blocks can be

individually unlocked by the Block Unlock com-

mand.

Two Bus Write cycles are required to issue the

Block Lock-Down command.

s The first bus cycle sets up the Block Lock

command.

s The second Bus Write cycle latches the block

address.

The lock status can be monitored for each block

using the Read Electronic Signature command.

Locked-Down blocks revert to the locked (and not

locked-down) state when the device is reset on

power-down. Table. 13 shows the Lock Status af-

ter issuing a Block Lock-Down command. Refer to

the section, Block Locking, for a detailed explana-

tion and Appendix C, Figure 34, Locking Opera-

tions Flowchart and Pseudo Code, for a flowchart

for using the Lock-Down command.

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