s29jl064j Meet Spansion Inc., s29jl064j Datasheet - Page 26

• Manufacturer Part Number: s29jl064j
• Description: 64 Megabit 8m X 8-bit/4m X 16-bit Cmos 3.0 Volt-only, Simultaneous Read/write Flash Memory
• Manufacturer: Meet Spansion Inc.

8.13
26
8.13.1
8.13.2
Secured Silicon Region
Factory Locked: Secured Silicon Region Programmed and Protected At the
Factory
Customer Lockable: Secured Silicon Region NOT Programmed or Protected
At the Factory
The Secured Silicon Region feature provides a Flash memory region that enables permanent part
identification through an Electronic Serial Number (ESN). The Secured Silicon Region is 256 bytes in length,
and may shipped unprotected, allowing customers to utilize that sector in any manner they choose, or may
shipped locked at the factory (upon customer request). The Secured Silicon Indicator Bit data will be 81h if
factory locked, 41h if customer locked, or 01h if neither. Refer to
The system accesses the Secured Silicon Region through a command sequence (see
Region/Exit Secured Silicon Region Command Sequence on page
Secured Silicon Region command sequence, it may read the Secured Silicon Region by using the addresses
normally occupied by the boot sectors. This mode of operation continues until the system issues the Exit
Secured Silicon Region 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 first 256 bytes of Sector 0. Note
that the ACC function and unlock bypass modes are not available when the Secured Silicon Region is
enabled.
In a factory locked device, the Secured Silicon Region is protected when the device is shipped from the
factory. The Secured Silicon Region cannot be modified in any way. The device is preprogrammed with both a
random number and a secure ESN. The 8-word random number is at addresses 000000h–000007h in word
mode (or 000000h–00000Fh in byte mode). The secure ESN is programmed in the next 8 words at addresses
000008h–00000Fh (or 000010h–00001Fh in byte mode). The device is available preprogrammed with one of
the following:
 A random, secure ESN only
 Customer code through Spansion programming services
 Both a random, secure ESN and customer code through Spansion programming services
Contact an your local sales office for details on using Spansion programming services.
If the security feature is not required, the Secured Silicon Region can be treated as an additional Flash
memory space. The Secured Silicon Region can be read any number of times, but can be programmed and
locked only once. Note that the accelerated programming (ACC) and unlock bypass functions are not
available when programming the Secured Silicon Region.
 Write the three-cycle Enter Secured Silicon Region command sequence, and then follow the in-system
 To verify the protect/unprotect status of the Secured Silicon Region, follow the algorithm shown in
Once the Secured Silicon Region is locked and verified, the system must write the Exit Secured Silicon
Region command sequence to return to reading and writing the remainder of the array.
The Secured Silicon Region lock must be used with caution since, once locked, there is no procedure
available for unlocking the Secured Silicon Region and none of the bits in the Secured Silicon Region
memory space can be modified in any way.
sector protect algorithm as shown in
V
voltage. Note that this method is only applicable to the Secured Silicon Region.
Figure 8.3 on page
ID
. This allows in-system protection of the Secured Silicon Region without raising any device pin to a high
27.
Figure 8.2 on page
S29JL064J
D a t a
S h e e t
25, except that RESET# may be at either V
Table 8.5 on page 21
32). After the system has written the Enter
S29JL064J_00_03 April 7, 2011
Enter Secured Silicon
for more details.
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or