S29AL016M datasheet(21/62 Pages) SPANSION

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October 11, 2006 S29AL016M_00_A7

S29AL016M

Data

Sheet

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 cannot be changed, which prevents cloning of a factory locked part. This en-

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

The device is offered with the Secured Silicon Sector either customer lockable

(standard shipping option) or factory locked (contact a sales office or represen-

tative for ordering information). The customer-lockable version is shipped with

the Secured Silicon Sector unprotected, allowing customers to program the sec-

tor 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 re-

place 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:

Table 5. Secured Silicon Sector Addressing

The system accesses the Secured Silicon Sector through a command sequence

(see “Enter Secured Silicon Sector/Exit Secured Silicon Sector Command Se-

quence”). After the system has written the Enter Secured Silicon Sector

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

dresses given in Table 5. This mode of operation continues until the system

issues the Exit Secured Silicon Sector command sequence, or until power is re-

moved 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.

Secured Silicon Sector Address

Range

Customer

Lockable

ESN Factory

Locked

ExpressFlash

Factory Locked

x16

0F8000h–

0F8007h

1F0000h-

1F000Fh

Determined by

customer

ESN

ESN or determined

by customer

0F8008h–

0F807Fh

1F0010h-

1F00FFh

Unavailable

Determined

by customer

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