MBM29QM12DH Fujitsu Microelectronics, Inc., MBM29QM12DH Datasheet - Page 37

• Manufacturer Part Number: MBM29QM12DH
• Description: Page Mode Flash Memory 128m 8m X 16 Bit
• Manufacturer: Fujitsu Microelectronics, Inc.

36
MBM29QM12DH
HiddenROM Entry Command
HiddenROM Program Command
HiddenROM Protect Command
SECTOR-ERASE ARCHITECTURE”. To terminate operation, it is necessary to write the read/reset command
sequence into the register.
The device has a HiddenROM area with One Time Protect function. This area is to enter the security code and
to unable the change of the code once set. Programming is allowed in this area until it is protected. However,
once it gets protected, it is impossible to unprotect. Therefore, extreme caution is required.
The HiddenROM area is 128 words (64 words for factory and 64 words for customer). This area is normally the
“outermost” 4 Kwords boot block area. Therefore, write the HiddenROM entry command sequence to enter the
HiddenROM area. It is called HiddenROM mode when the HiddenROM area appears.
Sectors other than the boot block area (SA0) can be read during HiddenROM mode. Read/program of the
HiddenROM area is possible during HiddenROM mode. Write the HiddenROM reset command sequence to exit
the HiddenROM mode. The bank address of the HiddenROM should be set on the third cycle of this reset
command sequence.
In HiddenROM mode, the simultaneous operation cannot be executed multi-function mode between the
HiddenROM area and the Bank A.
The following commands are unavailable when the HiddenROM is enabled. Issuing the following commands
while the HiddenROM is enabled results in the command being ignored.
1. CFI
2. Set to Fast Mode
3. Fast Program
4. Reset from Fast Mode
5. Program and Sector Erase Suspend
6. Program and Sector Erase Resume
The HiddenROM Entry command is allowed when the device is in either program or erase suspend modes. If
the HiddenROM is enabled, the program or erase suspend command is ignored. This prevents resuming either
programming or erasure on the HiddenROM if the overlayed sector was undergoing programming or erasure. It
is the responsibility of the software to resume the program or erasure of a suspended program or erase after
exiting the HiddenROM.
To program the data to the HiddenROM area, write the HiddenROM program command sequence during
HiddenROM mode. This command is the same as the program command in usual except to write the command
during HiddenROM mode. Therefore the detection of completion method is the same as in the past, using the
DQ
other than the HiddenROM area is selected to program, data of the address will be changed.
The method to protect the HiddenROM is to apply high voltage (V
HiddenROM area and (A
HiddenROM mode. To verify the protect circuit, apply high voltage (V
A
the protect setting is completed. “0” will appear on DQ
And the device has also HiddenROM protect command wirhout V
Table” in “ DEVICE BUS OPERATION”.
Other sector will be effected if the address other than those for HiddenROM 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.
0
) (0, 0, 0, 1, 1, 0, 1, 0) and the sector address in the HiddenROM area, and read. When “1” appears on DQ
7
data polling, and DQ
7
, A
6
toggle bit. Need to pay attention to the address to be programmed. If the address
6
, A
5
, A
-60
4
, A
3
, A
2
, A
1
, A
0
)
(0, 0, 0, 1, 1, 0, 1, 0), and apply the write pulse during the
0
if it is not protected. Please apply write pulse agian.
ID
. See “MBM29QM12DH Command Definitions
ID
) to A
ID
) to A
9
and OE, set the sector address in the
9
, specify (A
7
, A
6
, A
5
, A
4
, A
3
, A
2
, A
1
0
,
,