MBM29PL3200BE Fujitsu Microelectronics, Inc., MBM29PL3200BE Datasheet - Page 26

• Manufacturer Part Number: MBM29PL3200BE
• Description: Page Mode Flash Memory 32 M 2 M X 16/1 M X 32 Bit
• Manufacturer: Fujitsu Microelectronics, Inc.

26
MBM29PL3200TE/BE
Hidden ROM (Hi-ROM) Region
Hidden ROM (Hi-ROM) Entry Command
Hidden ROM (Hi-ROM) Program Command
Hidden ROM (Hi-ROM) Protect Command
The Hi-ROM feature provides a Flash memory region that the system may access through a new command
sequence. This is primarily intended for customers who wish to use an Electronic Serial Number (ESN) in the
device with the ESN protected against modification. Once the Hi-ROM region is protected, any further modifi-
cation of that region is impossible. This ensures the security of the ESN once the product is shipped to the field.
The Hi-ROM region is 512 words in length. After the system has written the Enter Hi-ROM command sequence,
it may read the Hidden ROM region by using device addresses A
care). That is, the device sends only program command that would normally be sent to the address to the Hi-
ROM region. This mode of operation continues until the system issues the Exit Hi-ROM command sequence,
or until power is removed from the device. On power-up, or following a hardware reset, the device reverts to
sending commands to the address.
The device has a Hidden ROM area with One Time Protect function. This area is to enter the security code and
to unable the change of the code once set. Program/erase is possible in this area until it is protected. However,
once it is protected, it is impossible to unprotect, so please use this with caution.
Hidden ROM area is 512 words. This area is normally the “outermost” 16 K word boot block area. Therefore,
write the Hidden ROM entry command sequence to enter the Hidden ROM area. It is called Hidden ROM mode
when the Hidden ROM area appears.
To program the data to the Hidden ROM area, write the Hidden ROM program command sequence during Hidden
ROM mode. This command is the same as the program command in usual except to write the command during
Hidden ROM mode. Therefore the detection of completion method is the same as in the past, using the DQ
data polling, and DQ
than the Hidden ROM area is selected to program, data of the address will be changed.
The method to protect the Hidden ROM is to apply high voltage (V
the Hidden ROM area and (A
mode. To verify the protect circuit, apply high voltage (V
the sector address in the Hidden ROM area, and read. When “1” appears on DQ
“0” will appear on DQ
be used for the above method because other than the Hidden ROM mode, it is the same as the sector protect
in the past. Please refer to “Function Explanation Secor Protection” for details of the sector protect setting.
Other sector will be effected if the address other than those for Hidden ROM area is selected for the sector
address, so please be carefull. Once it is protected, protection can not be cancelled, so please pay the closest
attention.
6
0
if it is not protected. Please apply write pulse agian. The same command sequence could
toggle bit. Need to pay attention to the address to be programmed. If the address other
6
, A
3
, A
2
, A
1
, A
0
70/90
)
(0, 0, 0, 1, 0), and apply the write pulse during the Hidden ROM
ID
) to A
9
, specify (A
7
to A
ID
) to A
0
(A
11
9
6
, A
and OE, set the sector address in
to A
0
, the protect setting is completed.
3
, A
8
2
are “00”, A
, A
1
, A
0
)
(0, 0, 0, 1, 0) and
19
to A
12
are don’t
7