AM29PDL640G AMD [Advanced Micro Devices], AM29PDL640G Datasheet - Page 24

• Manufacturer Part Number: AM29PDL640G
• Description: 64 Megabit (4 M x 16-Bit) CMOS 3.0 Volt-only, Simultaneous Read/Write Flash Memory with Enhanced VersatileIOTM Control
• Manufacturer: AMD [Advanced Micro Devices]

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
sectors can be programmed or erased by selecting the
sector addresses. Once V
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.
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.
22
Notes:
1. All protected sectors unprotected (If
2. All previously protected sectors are protected once
Figure 2. Temporary Sector Unprotect Operation
sectors 0, 1, 140, 141 will remain protected).
again.
V
ID
. During this mode, formerly protected
Unprotect Completed
Program Operations
Temporary Sector
Perform Erase or
RESET# = V
RESET# = V
(Note 1)
(Note 2)
ID
START
is removed from the RE-
ID
IH
WP#/ACC
D A T A S H E E T
= V
Am29PDL640G
IL
,
AMD offers the device with the SecSi Sector either
facto r y locked or custo mer lockable. The 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
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,
but can be programmed and locked only once. Note
through the ExpressFlash service.
December 13, 2005