MBM29PL32TM90 datasheet(29/68 Pages) SPANSION

29 / 68 page

MBM29PL32TM/BM90/10

Query Command (CFI : Common Flash Memory Interface)

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

(DQ15 to DQ8) is “0”. Refer to the CFI code table. To terminate operation, it is necessary to write the Reset

command sequence into the register. (See “Common Flash Memory Interface Code” in sDEVICE BUS OPER-

ATION.)

HiddenROM Mode

(1) HiddenROM Region

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 A6 to A0 (A20 to A7 are all

“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.

(2) HiddenROM Entry Command

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.

MBM29PL32TM90 Datasheet(PDF) 29 Page - SPANSION