MBM29PL32BM Fujitsu Media Devices, MBM29PL32BM Datasheet - Page 29

• Manufacturer Part Number: MBM29PL32BM
• Description: (MBM29PL32TM/BM) FLASH MEMORY CMOS 32 M (4M X 8/2M X 16) BIT MirrorFlash
• Manufacturer: Fujitsu Media Devices

Query Command (CFI : Common Flash Memory Interface)
HiddenROM Mode
The CFI (Common Flash Memory Interface) specification outlines device and host system software interrogation
handshake which allows specific vendor-specified software algorithms to be used for entire families of devices.
This allows device-independent, JEDEC ID-independent, and forward-and backward-compatible software sup-
port for the specified flash device families. Refer to CFI specification in detail.
The operation is initiated by writing the query command (98h) into the command register. Following the command
write, a read cycle from specific address retrieves device information. Please note that output data of upper byte
(DQ
command sequence into the register. (See “Common Flash Memory Interface Code” in DEVICE BUS OPER-
ATION.)
The HiddenROM (HiddenROM) 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 HiddenROM region is protected, any
further modification of that region is impossible. This ensures the security of the ESN once the product is shipped
to the field.
The HiddenROM region is 256 bytes / 128 words in length. After the system writes the HiddenROM Entry
command sequence, it may read the HiddenROM region by using device addresses A
“0”). That is, the device sends only program command that would normally be sent to the address to the
HiddenROM region. This mode of operation continues until the system issues the Exit HiddenROM 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.
If you request Fujitsu to program the ESN in the device, please contact a Fujitsu representative for more infor-
mation.
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 256 bytes / 128 words. This area is in SA0 . 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 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 Hidden-
ROM mode. Note that any other commands should not be issued than the HiddenROM program/protection/reset
commands during the HiddenROM mode. When you issue the other commands including the suspend resume
capability, send the HiddenROM reset command first to exit the HiddenROM mode and then issue each com-
mand.
(1) HiddenROM Region
(2) HiddenROM Entry Command
15
to DQ
8
) is “0”. Refer to the CFI code table. To terminate operation, it is necessary to write the Reset
MBM29PL32TM/BM
6
to A
0
(A
20
to A
7
90/10
are all
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