S29WSXXXN Datasheet, PDF (59/95 Pages) SPANSION – 256/128/64 Megabit (16/8/4 M x 16-Bit) CMOS 1.8 Volt-only Simultaneous Read/Write, Burst Mode Flash Memory

Preliminary
10 SecSi^TM (Secured Silicon) Sector Flash Memory Region
The SecSi (Secured Silicon) Sector provides an extra Flash memory region that enables per-
manent part identification through an Electronic Serial Number (ESN). The SecSi Sector is
256 words in length that consists of 128 words for factory data and 128 words for customer-
secured areas. All SecSi reads outside of the 256-word address range will return invalid data.
The Factory Indicator Bit, DQ7, (at Autoselect address 03h) is used to indicate whether or not
the Factory SecSi Sector is locked when shipped from the factory. The Customer Indicator Bit
(DQ6) is used to indicate whether or not the Customer SecSi Sector is locked when shipped
from the factory.
Please note the following general conditions:
„ While SecSi Sector access is enabled, simultaneous operations are allowed except for
Bank 0.
„ On power-up, or following a hardware reset, the device reverts to sending commands to
the normal address space.
„ Reads can be performed in the Asynchronous or Synchronous mode.
„ Burst mode reads within SecSi Sector will wrap from address FFh back to address 00h.
„ Reads outside of sector 0 will return memory array data.
„ Continuous burst read past the maximum address is undefined.
„ Sector 0 is remapped from memory array to SecSi Sector array.
„ Once the SecSi Sector Entry Command is issued, the SecSi Sector Exit command must
be issued to exit SecSi Sector Mode.
„ The SecSi Sector is not accessible when the device is executing an Embedded Program
or Embedded Erase algorithm.
Sector
Customer
Factory
Table 10.1. SecSi^TM Sector Addresses
Sector Size
128 words
128 words
Address Range
000080h-0000FFh
000000h-00007Fh
10.1 Factory SecSi^TM Sector
The Factory SecSi Sector is always protected when shipped from the factory and has the Fac-
tory Indicator Bit (DQ7) permanently set to a “1”. This prevents cloning of a factory locked
part and ensures the security of the ESN and customer code once the product is shipped to
the field.
These devices are available pre programmed with one of the following:
„ A random, 8 Word secure ESN only within the Factory SecSi Sector
„ Customer code within the Customer SecSi Sector through the Spansion^TM programming
service.
„ Both a random, secure ESN and customer code through the Spansion programming ser-
vice.
Customers may opt to have their code programmed through the Spansion programming ser-
vices. Spansion programs the customer's code, with or without the random ESN. The devices
are then shipped from the Spansion factory with the Factory SecSi Sector and Customer SecSi
Sector permanently locked. Contact your local representative for details on using Spansion
programming services.
October 29, 2004 S29WSxxxN_00_F0
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