S29GL032A datasheet(38/88 Pages) SPANSION

38 / 88 page

S29GLxxxA MirrorBit™ Flash Family

S29GLxxxA_00_A2 January 28, 2005

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Inf o rmation

Secured Silicon Sector Flash Memory Region

The Secured Silicon Sector feature provides a Flash memory region that enables

permanent part identification through an Electronic Serial Number (ESN). The

Secured Silicon Sector is 256 bytes in length, and uses a Secured Silicon Sector

Indicator Bit (DQ7) to indicate whether or not the Secured Silicon Sector is locked

when shipped from the factory. This bit is permanently set at the factory and can-

not be changed, which prevents cloning of a factory locked part. This ensures the

security of the ESN once the product is shipped to the field.

The factory offers the device with the Secured Silicon Sector either customer

lockable (standard shipping option) or factory locked (contact a Spansion sales

representative for ordering information). The customer-lockable version is

shipped with the Secured Silicon Sector unprotected, allowing customers to pro-

gram the sector after receiving the device. The customer-lockable version also

has the Secured Silicon Sector Indicator Bit permanently set to a “0.” The factory-

locked version is always protected when shipped from the factory, and has the

Secured Silicon Sector Indicator Bit permanently set to a “1.” Thus, the Secured

Silicon Sector Indicator Bit prevents customer-lockable devices from being used

to replace devices that are factory locked. Note that the ACC function and unlock

bypass modes are not available when the Secured Silicon Sector is enabled.

The Secured Silicon sector address space in this device is allocated as follows:

The system accesses the Secured Silicon Sector through a command sequence

(see “Write Protect (WP#)”). After the system has written the Enter Secured Sil-

icon Sector command sequence, it may read the Secured Silicon Sector by using

the addresses normally occupied by the first sector (SA0). This mode of operation

continues until the system issues the Exit Secured Silicon Sector command se-

quence, or until power is removed from the device. On power-up, or following a

hardware reset, the device reverts to sending commands to sector SA0.

Customer Lockable: Secured Silicon Sector NOT Programmed or

Protected At the Factory

Unless otherwise specified, the device is shipped such that the customer may

program and protect the 256-byte Secured Silicon sector.

The system may program the Secured Silicon Sector using the write-buffer, ac-

celerated and/or unlock bypass methods, in addition to the standard

programming command sequence. See “Command Definitions” .

Programming and protecting the Secured Silicon Sector must be used with cau-

tion since, once protected, there is no procedure available for unprotecting the

Secured Silicon Sector area and none of the bits in the Secured Silicon Sector

memory space can be modified in any way.

The Secured Silicon Sector area can be protected using one of the following

procedures:

Write the three-cycle Enter Secured Silicon Sector Region command se-

quence, and then follow the in-system sector protect algorithm as shown in

Secured Silicon Sector Address Range

x16

Standard Factory

Locked

ExpressFlash Factory

Locked

Customer Lockable

000000h–000007h

000000h-00000Fh

ESN

ESN or determined by

customer

Determined by customer

000008h–00007Fh

000010h-0000FFh

Unavailable

Determined by customer

S29GL032A Datasheet(PDF) 38 Page - SPANSION

S29GL032A Datasheet(HTML) 38 Page - SPANSION

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