S71GL064A08 SPANSION [SPANSION], S71GL064A08 Datasheet - Page 36

• Manufacturer Part Number: S71GL064A08
• Description: STACKED MULTI CHIP PRODUCT FLASH MEMORY AND RAM
• Manufacturer: SPANSION [SPANSION]

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Secured Silicon Sector Flash Memory Region
The Secured Silicon Sector feature provides a Flash memory region that enables permanent
part identification 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 perma-
nently 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.
The factory offers the device with the Secured Silicon Sector either customer lockable (stan-
dard shipping option) or factory locked (contact a Spansion sales representative for ordering
information). The customer-lockable version is shipped with the Secured Silicon Sector un-
protected, allowing customers to program the sector after receiving the device. The
customer-lockable version also has the Secured Silicon Sector Indicator Bit permanently set
to a “0.” The factory-locked version is always protected when shipped from the factory, and
has the Secured Silicon Sector Indicator Bit permanently set to a “1.” Thus, the Secured Sil-
icon 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 Silicon Sector is enabled.
The Secured Silicon sector address space in this device is allocated as follows:
The system accesses the Secured Silicon Sector through a command sequence (see “Write
Protect (WP#)”). After the system has written the Enter Secured Silicon Sector command se-
quence, 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 issues the Exit Se-
cured Silicon 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: 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 bypass methods, in addition to the standard programming command sequence. See
Command
Programming and protecting the Secured Silicon Sector 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 modified in any way.
The Secured Silicon Sector area can be protected using one of the following procedures:
Secured Silicon Sector
Write the three-cycle Enter Secured Silicon Sector Region command sequence, and then
follow the in-system sector protect algorithm as shown in
may be at either V
without raising any device pin to a high voltage. Note that this method is only applicable
to the Secured Silicon Sector.
To verify the protect/unprotect status of the Secured Silicon Sector, follow the algorithm
shown in
000000h–000007h
000008h–00007Fh
Address Range
Definitions.
Figure
1.
IH
or V
Customer Lockable
Determined by
ID
A d v a n c e
customer
S71GL064A based MCPs
. This allows in-system protection of the Secured Silicon Sector
ESN Factory Locked
I n f o r m a t i o n
Unavailable
ESN
ESN or determined by
Figure
Factory Locked
Determined by
ExpressFlash
customer
customer
2, except that RESET#
S71GL064A_00_A2 February 8, 2005