AM29PDL640G datasheet(23/61 Pages) SPANSION

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Am29PDL640G

February 26, 2003

P R E L I M INARY

Temporary Sector Unprotect

This feature allows temporary unprotection of previ-

ously protected sectors to change data in-system. The

Sector Unprotect mode is activated by setting the RE-

SET# pin to V

ID. During this mode, formerly protected

sectors can be programmed or erased by selecting the

sector addresses. Once V

ID is removed from the RE-

SET# pin, all the previously protected sectors are

protected again. Figure 2 shows the algorithm, and

Figure 22 shows the timing diagrams, for this feature.

Figure 2.

Temporary Sector Unprotect Operation

SecSi™ (Secured Silicon) Sector

Flash Memory Region

The SecSi (Secured Silicon) Sector feature provides a

Flash memory region that enables permanent part

identification through an Electronic Serial Number

(ESN). The SecSi Sector is up to 128 words in length,

and uses a SecSi Sector Indicator Bit (DQ7) to indi-

cate whether or not the SecSi 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 ensures the secu-

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

AMD offers the device with the SecSi Sector either

factor y lock ed or customer loc kable. T he fac-

tory-locked version is always protected when shipped

from the factory, and has the SecSi (Secured Silicon)

Sector Indicator Bit permanently set to a “1.” The cus-

tomer-lockable version is shipped with the SecSi Sec-

tor unprotected, allowing customers to utilize the

sector in any manner they choose. The customer-lock-

able version has the SecSi (Secured Silicon) Sector

Indicator Bit permanently set to a “0.” Thus, the SecSi

Sector Indicator Bit prevents customer-lockable de-

vices from being used to replace devices that are fac-

tory locked.

The system accesses the SecSi Sector through a

command sequence (see “Enter SecSi™ Sector/Exit

SecSi Sector Command Sequence”). After the system

has written the Enter SecSi Sector command se-

quence, it may read the SecSi Sector by using the ad-

dresses normally occupied by the boot sectors. This

mode of operation continues until the system issues

the Exit SecSi Sector command sequence, or until

power is removed from the device. On power-up, or

following a hardware reset, the device reverts to send-

ing commands to the normal address space. Note that

the ACC function and unlock bypass modes are not

available when the SecSi Sector is enabled.

Factory Locked: SecSi Sector Programmed and

Protected At the Factory

In a factory locked device, the SecSi Sector is pro-

tected when the device is shipped from the factory.

The SecSi Sector cannot be modified in any way. The

device is preprogrammed with both a random number

and a secure ESN. The SecSi Sector is located at ad-

dresses 000000h–00007Fh in Persistent Protection

mode, and at addresses 000005h–00007Fh in Pass-

word Protection mode. The device is available prepro-

grammed with one of the following:

■ A random, secure ESN only

■ Customer code through the ExpressFlash service

■ Both a random, secure ESN and customer code

through the ExpressFlash service.

Customers may opt to have their code programmed by

AMD through the AMD ExpressFlash service. AMD

programs the customer’s code, with or without the ran-

dom ESN. The devices are then shipped from AMD’s

factory with the SecSi Sector permanently locked.

Contact an AMD representative for details on using

AMD’s ExpressFlash service.

Customer Lockable: SecSi Sector NOT

Programmed or Protected At the Factory

If the security feature is not required, the SecSi Sector

can be treated as an additional Flash memory space.

The SecSi Sector can be read any number of times,

START

Perform Erase or

Program Operations

RESET# = V

Temporary Sector

Unprotect Completed

(Note 2)

RESET# = V

(Note 1)

Notes:

1. All protected sectors unprotected (If

WP#/ACC = V

IL,

sectors 0, 1, 140, 141 will remain protected).

2. All previously protected sectors are protected once

again.

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