L320MT90QI Advanced Micro Devices, L320MT90QI Datasheet - Page 20

• Manufacturer Part Number: L320MT90QI
• Description: 32 Megabit 2 M X 16-bit/4 M X 8-bit Mirrorbit 3.0 Volt-only Boot Sector Flash Memory - Advanced Micro Devices
• Manufacturer: Advanced Micro Devices

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.
20
000000h–000007h
000008h–00007Fh
Address Range
SecSi Sector
Table 7. SecSi Sector Contents
Determined by
Customer
Lockable
customer
ESN Factory
Unavailable
Locked
ESN
Factory Locked
ExpressFlash
Determined by
determined by
customer
customer
D A T A S H E E T
ESN or
Am29LV320MT/B
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
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:
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.
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 V
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.
Command
Definitions.
May 16, 2003
IH
or V
ID
. This