AM29LV033MU datasheet(21/61 Pages) SPANSION

21 / 61 page

September 12, 2006

Am29LV033MU

DA TA

SH EET

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 256 bytes in length, and

uses a SecSi Sector Indicator Bit (DQ7) to indicate

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

customer lockable (standard shipping option) or fac-

tory locked (contact an AMD sales representative for

ordering information). The customer-lockable version

is shipped with the SecSi Sector unprotected, allowing

customers to program the sector after receiving the

device. The customer-lockable version also has the

SecSi Sector Indicator Bit permanently set to a “0.”

The factory-locked version is always protected when

shipped from the factory, and has the SecSi (Secured

Silicon) Sector Indicator Bit permanently set to a “1.”

Thus, the SecSi Sector Indicator Bit prevents cus-

tomer-lockable devices from being used to replace de-

vices that are factory locked. Note that the ACC

function and unlock bypass modes are not available

when the SecSi Sector is enabled.

The SecSi sector address space in this device is allo-

cated as follows:

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 first sector (SA0).

This mode of operation continues until the system is-

sues 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

sending commands to sector SA0.

Customer Lockable: SecSi 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 SecSi sector.

The system may program the SecSi Sector using the

write-buffer, accelerated and/or unlock bypass meth-

ods, in addition to the standard programming com-

mand sequence. See Command Definitions.

Programming and protecting the SecSi Sector must be

used with caution since, once protected, there is no

procedure available for unprotecting the SecSi Sector

area and none of the bits in the SecSi Sector memory

space can be modified in any way.

The SecSi Sector area can be protected using one of

the following procedures:

■ Write the three-cycle Enter SecSi Sector Region

command sequence, and then follow the in-system

sector protect algorithm as shown in Figure 2, ex-

cept that RESET# may be at either VIH or VID. This

allows in-system protection of the SecSi Sector

without raising any device pin to a high voltage.

Note that this method is only applicable to the SecSi

Sector.

■ To verify the protect/unprotect status of the SecSi

Sector, follow the algorithm shown in Figure 3.

Once the SecSi Sector is programmed, locked and

verified, the system must write the Exit SecSi Sector

Region command sequence to return to reading and

writing within the remainder of the array.

Factory Locked: SecSi Sector Programmed and

Protected At the Factory

In devices with an ESN, the SecSi Sector is protected

when the device is shipped from the factory. The SecSi

Sector cannot be modified in any way. An ESN Factory

Locked device has an 16-byte random ESN at ad-

dresses 000000h–000007h. Please contact your local

AMD sales representative for details on ordering ESN

Factory Locked devices.

Customers may opt to have their code programmed by

AMD through the AMD ExpressFlash service (Express

Flash Factory Locked). 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.

Table 5.

SecSi Sector Contents

SecSi Sector

Address Range

Customer

Lockable

ESN Factory

Locked

ExpressFlash

Factory Locked

000000h–000007h

Determined by

customer

ESN

ESN or

determined by

customer

000008h–00007Fh

Unavailable

Determined by

customer

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