M29W320E ST Microelectronics, M29W320E Datasheet - Page 39

• Manufacturer Part Number: M29W320E
• Description: 32 Mbit (4Mb x8 or 2Mb x16 / Boot Block) 3V Supply Flash Memory
• Manufacturer: ST Microelectronics

APPENDIX C. EXTENDED MEMORY BLOCK
The M29W320E has an extra block, the Extended
Block, that can be accessed using a dedicated
command.
This Extended Block is 32 KWords in x16 mode
and 64 KBytes in x8 mode. It is used as a security
block (to provide a permanent security identifica-
tion number) or to store additional information.
The Extended Block is either Factory Locked or
Customer Lockable, its status is indicated by bit
DQ7. This bit is permanently set to either ‘1’ or ‘0’
at the factory and cannot be changed. When set to
‘1’, it indicates that the device is factory locked and
the Extended Block is protected. When set to ‘0’, it
indicates that the device is customer lockable and
the Extended Block is unprotected. Bit DQ7 being
permanently locked to either ‘1’ or ‘0’ is another
security feature which ensures that a customer
lockable device cannot be used instead of a facto-
ry locked one.
Bit DQ7 is the most significant bit in the Extended
Block Verify Code and a specific procedure must
be followed to read it. See “Extended Memory
Block Verify Code
Operations, BYTE = V
BYTE = V
bit DQ7.
The Extended Block can only be accessed when
the device is in Extended Block mode. For details
of how the Extended Block mode is entered and
exited, refer to the
mand
graphs, and to
16-bit mode, BYTE = V
mode, BYTE = V
Table 28. Extended Block Address and Data
Note: 1. See
M29W320ET
M29W320EB
Device
and
IH
Table 20.
Exit Extended Block Command
, respectively, for details of how to read
Table 4.
IL
3F0010h-3FFFFFh
” in
3F0000h-3F000Fh
000010h-00FFFFh
and
”, respectively.
000000h-00000Fh
Enter Extended Block Com-
Table
Table 2.
and
IH
IL
x8
” and
21., Top and Bottom Boot Block Addresses.
and
Table
and
“Commands, 8-bit
Address
Bus Operations,
5.,
Table
“Commands,
1F8008h-1FFFFFh
000008h-007FFFh
1F8000h-1F8007h
000000h-000007h
(1)
3.,
para-
Bus
x16
Factory Locked Extended Block
In devices where the Extended Block is factory
locked, the Security Identification Number is writ-
ten to the Extended Block address space (see
ble 28., Extended Block Address and
factory. The DQ7 bit is set to ‘1’ and the Extended
Block cannot be unprotected.
Customer Lockable Extended Block
A device where the Extended Block is customer
lockable is delivered with the DQ7 bit set to ‘0’ and
the Extended Block unprotected. It is up to the
customer to program and protect the Extended
Block but care must be taken because the protec-
tion of the Extended Block is not reversible.
There are two ways of protecting the Extended
Block:
Once the Extended Block is programmed and pro-
tected, the Exit Extended Block command must be
issued to exit the Extended Block mode and return
the device to Read mode.
Issue the Enter Extended Block command to
place the device in Extended Block mode,
then use the In-System Technique with RP
either at V
In-System Technique
corresponding flowcharts,
Figure
technique).
Issue the Enter Extended Block command to
place the device in Extended Block mode,
then use the Programmer Technique (refer to
APPENDIX
the corresponding flowcharts,
Figure
technique).
Security Identification
Security Identification
Factory Locked
23., for a detailed explanation of the
21., for a detailed explanation of the
Unavailable
Unavailable
Number
Number
IH
D., Programmer Technique and to
or at V
M29W320ET, M29W320EB
ID
Data
(refer to
and to the
Customer Lockable
Figure 22.
Determined by
Determined by
APPENDIX
Figure 20.
Customer
Customer
Data) in the
and
39/46
and
D.,
Ta-