AM29LV320DB90WMF datasheet(20/55 Pages) SPANSION

20 / 55 page

Am29LV320D

November 15, 2004

SecSiTM Sector (Secured Silicon) Flash

Memory Region

The Secured Silicon Sector (SecSi Sector) fea-

ture provides a Flash memory region that en-

ables permanent part identification through an

Electronic Serial Number (ESN). The SecSi Sec-

tor 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 security of the

ESN once the product is shipped to the field.

Note that the Am29LV320D has a SecSi

Sector size of 64 Kbytes. AMD devices des-

ignated as replacements or substitutes,

such as the Am29LV320M, have 256 bytes.

This should be considered during system

design.

AMD offers the device with the SecSi Sector ei-

ther factory locked or customer lockable. The

factory-locked version is always protected

when shipped from the factory, and has the

SecSi Sector Indicator Bit permanently set to a

“1.” The customer-lockable version is shipped

with the SecSi Sector unprotected, allowing

customers to utilize the that sector in any man-

ner they choose. The customer-lockable ver-

s io n ha s t he S e cS i Se ct or In di ca to r B i t

permanently set to a “0.” Thus, the SecSi Sec-

tor Indicator Bit prevents customer-lockable

devices from being used to replace devices that

are factory locked.

The system accesses the SecSi Sector through

a command sequence (see “Enter SecSiTM Sec-

tor/Exit SecSi Sector Command Sequence” on

page 26). After the system writes the Enter

SecSi Sector command sequence, it may read

the SecSi Sector by using the addresses nor-

mally 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 sending commands to the

boot sectors.

Factory Locked: SecSi Sector Programmed

and Protected at the Factory

In a factory locked device, the SecSi Sector is

protected when the device is shipped from the

factory. The SecSi Sector cannot be modified in

any way. 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.

In devices that have an ESN, a Bottom Boot de-

vice has the 16-byte (8-word) ESN in sector 0

at addresses 00000h–0000Fh in byte mode (or

00000h–00007h in word mode). In the Top

Boot device the ESN is in sector 63 at ad-

dresses 3F0000h–3F000Fh in byte mode (or

1F8000h–1F8007h in word mode). Note that in

upcoming top boot versions of this device, the

ESN is located in sector 70 at addresses

3F E0 00 h – 3 F E 0 0Fh i n b y t e mo de ( o r

1FF000h–1FF007h in word mode).

Customers may opt to have their code pro-

grammed by AMD through the AMD Express-

Flash service. AMD programs the customer’s

code, with or without the random ESN. The de-

vices 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

The customer lockable version allows the SecSi

Sector to be programmed once and then per-

manently locked after it ships from AMD. Note

that the Am29LV320D has a SecSi Sector

size of 64 Kbytes. AMD devices designated

as replacements or substitutes, such as

the Am29LV320M, have 256 bytes. This

should be considered during system de-

sign. Additionally, note the change in the

location of the ESN in upcoming top boot

factory locked devices. Note that the accel-

erated programming (ACC) and unlock bypass

functions are not available when programming

the SecSi Sector.

The SecSi Sector area can be protected using

the following procedures:

■

Write the three-cycle Enter SecSi Region

command sequence, and then follow the

in-system sector protect algorithm as shown

in Figure 2, on page 19, except 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 volt-

age. 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, on page 21.

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