M28W640FCT STMICROELECTRONICS [STMicroelectronics], M28W640FCT Datasheet - Page 13

• Manufacturer Part Number: M28W640FCT
• Description: 64 Mbit (4Mb x16, Boot Block) 3V Supply Flash Memory
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

During Program/Erase Suspend the Command In-
terface will accept the Program/Erase Resume,
Read Array, Read Status Register, Read Electron-
ic Signature and Read CFI Query commands. Ad-
ditionally, if the suspend operation was Erase then
the Program, Double Word Program, Quadruple
Word Program, Block Lock, Block Lock-Down or
Protection Program commands will also be ac-
cepted. The block being erased may be protected
by issuing the Block Protect, Block Lock or Protec-
tion Program commands. When the Program/
Erase Resume command is issued the operation
will complete. Only the blocks not being erased
may be read or programmed correctly.
During a Program/Erase Suspend, the device can
be placed in a pseudo-standby mode by taking
Chip Enable to V
Reset turns to V
See
& Resume Flowchart and Pseudo
ure 22., Erase Suspend & Resume Flowchart and
Pseudo
gram/Erase Suspend command.
Program/Erase Resume Command
The Program/Erase Resume command can be
used to restart the Program/Erase Controller after
a Program/Erase Suspend operation has paused
it. One Bus Write cycle is required to issue the
command. Once the command is issued subse-
quent Bus Read operations read the Status Reg-
ister.
See
& Resume Flowchart and Pseudo
ure 22., Erase Suspend & Resume Flowchart and
Pseudo
gram/Erase Resume command.
Protection Register Program Command
The Protection Register Program command is
used to Program the 128 bit user One-Time-Pro-
grammable (OTP) segment of the Protection Reg-
ister. The segment is programmed 16 bits at a
time. When shipped all bits in the segment are set
to ‘1’. The user can only program the bits to ‘0’.
Two write cycles are required to issue the Protec-
tion Register Program command.
■
■
Read operations output the Status Register con-
tent after the programming has started.
The segment can be protected by programming bit
1 of the Protection Lock Register (see
6., Protection Register Memory
to program a previously protected Protection Reg-
The first bus cycle sets up the Protection
Register Program command.
The second latches the Address and the Data
to be written to the Protection Register and
starts the Program/Erase Controller.
APPENDIX
APPENDIX
Code, for flowcharts for using the Pro-
Code, for flowcharts for using the Pro-
IL
C.,
C.,
.
IH
. Program/Erase is aborted if
Figure 20., Program Suspend
Figure 20., Program Suspend
Map). Attempting
Code, and
Code, and
Figure
Fig-
Fig-
ister will result in a Status Register error. The pro-
tection of the Protection Register is not reversible.
The Protection Register Program cannot be sus-
pended.
Block Lock Command
The Block Lock command is used to lock a block
and prevent Program or Erase operations from
changing the data in it. All blocks are locked at
power-up or reset.
Two Bus Write cycles are required to issue the
Block Lock command.
■
■
The lock status can be monitored for each block
using the Read Electronic Signature command.
Table 10.
a Block Lock command.
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 Blocks Unlock
command. Refer to the section, Block Locking, for
a detailed explanation.
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.
■
■
The lock status can be monitored for each block
using the Read Electronic Signature command.
Table 10.
a Block Unlock command. Refer to the section,
Block Locking, for a detailed explanation.
Block Lock-Down Command
A locked block cannot be Programmed or Erased,
or have its protection status changed when WP is
low, V
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.
■
■
The lock status can be monitored for each block
using the Read Electronic Signature command.
Locked-Down blocks revert to the locked (and not
The first bus cycle sets up the Block Lock
command.
The second Bus Write cycle latches the block
address.
The first bus cycle sets up the Block Unlock
command.
The second Bus Write cycle latches the block
address.
The first bus cycle sets up the Block Lock
command.
The second Bus Write cycle latches the block
address.
IL
. When WP is high, V
shows the protection status after issuing
shows the protection status after issuing
M28W640FCT, M28W640FCB
IH,
the Lock-Down
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