AM29LV320MB SPANSION [SPANSION], AM29LV320MB Datasheet - Page 23

• Manufacturer Part Number: AM29LV320MB
• Manufacturer: SPANSION [SPANSION]

Secured Silicon Sector Flash
Memory Region
The Secured Silicon Sector feature provides a Flash
memory region that enables permanent part identifica-
tion 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 per-
manently 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.
AMD offers the device with the Secured Silicon Sector
either customer lockable (standard shipping option) or
factory locked (contact an AMD sales representative
for ordering information). The customer-lockable ver-
sion is shipped with the Secured Silicon Sector unpro-
tected, allowing customers to program the sector after
receiving the device. The customer-lockable version
also has the Secured Silicon Sector Indicator Bit per-
manently set to a “0.” The factory-locked version is al-
ways protected when shipped from the factory, and
has the Secured Silicon (Secured Silicon) Sector Indi-
cator 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 Sil-
icon Sector is enabled.
The Secured Silicon sector address space in this de-
vice is allocated as follows:
The system accesses the Secured Silicon Sector
through a command sequence (see
i c o n S e c t o r / E x i t S e c u r e d S i l i c o n S e c t o r
Command
the Enter Secured Silicon 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 is-
sues 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 re-
verts to sending commands to sector SA0.
26518C3 January 31, 2007
000008h–00007Fh
000000h–000007h
Secured Silicon
Sector Address
Table 7. Secured Silicon Sector Contents
Range
Sequence). After the system has written
Determined by
Customer
Lockable
customer
ESN Factory
Unavailable
Locked
ESN
Enter Secured Sil-
Factory Locked
ExpressFlash
Determined by
determined by
D A T A
customer
customer
ESN or
Am29LV320MT/B
S H E E T
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, accelerated and/or unlock by-
pass methods, in addition to the standard program-
ming command sequence. See
Programming and protecting the Secured Silicon Sec-
tor must be used with caution 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 modi-
fied 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
■ To verify the protect/unprotect status of the Secured
Once the Secured Silicon Sector is programmed,
locked and verified, the system must write the Exit Se-
cured Silicon Sector Region command sequence to
return to reading and writing within the remainder of
the array.
Factory Locked: Secured Silicon Sector
Programmed and Protected At the Factory
In devices with an ESN, the Secured Silicon Sector is
protected when the device is shipped from the factory.
The Secured Silicon Sector cannot be modified in any
way. An ESN Factory Locked device has an 16-byte
random ESN at addresses 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 Secured Silicon Sector
permanently locked. Contact an AMD representative
for details on using AMD’s ExpressFlash service.
Region command sequence, and then follow the
in-system sector protect algorithm as shown in
ure
V
Silicon Sector without raising any device pin to a
high voltage. Note that this method is only applica-
ble to the Secured Silicon Sector.
Silicon Sector, follow the algorithm shown in
3.
ID
. This allows in-system protection of the Secured
2, except that RESET# may be at either V
Command
Definitions.
Figure
IH
Fig-
21
or