S75WS256NDFBAWMB datasheet(64/216 Pages) SPANSION

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S75WS256Nxx Based MCPs

S75WS-N-00_A0 February 17, 2005

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Inf o rmation

11 Secured Silicon Sector Flash Memory Region

The Secured Silicon Sector provides an extra Flash memory region that enables permanent part

identification through an Electronic Serial Number (ESN). The Secured Silicon Sector is 256 words

in length that consists of 128 words for factory data and 128 words for customer-secured areas.

All Secured Silicon reads outside of the 256-word address range returns invalid data. The Factory

Indicator Bit, DQ7, (at Autoselect address 03h) is used to indicate whether or not the Factory Se-

cured Silicon Sector is locked when shipped from the factory. The Customer Indicator Bit (DQ6)

is used to indicate whether or not the Customer Secured Silicon Sector is locked when shipped

from the factory.

Please note the following general conditions:

While Secured Silicon 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 Secured Silicon Sector wrap from address FFh back to address 00h.

Reads outside of sector 0 return memory array data.

Continuous burst read past the maximum address is undefined.

Sector 0 is remapped from memory array to Secured Silicon Sector array.

Once the Secured Silicon Sector Entry Command is issued, the Secured Silicon Sector Exit

command must be issued to exit Secured Silicon Sector Mode.

The Secured Silicon Sector is not accessible when the device is executing an Embedded Pro-

gram or Embedded Erase algorithm.

11.1

Factory Secured SiliconSector

The Factory Secured Silicon Sector is always protected when shipped from the factory and has

the Factory 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 Secured Silicon Sector

Customer code within the Customer Secured Silicon Sector through the SpansionTM program-

ming service.

Both a random, secure ESN and customer code through the Spansion programming service.

Customers may opt to have their code programmed through the Spansion programming services.

Spansion programs the customer's code, with or without the random ESN. The devices are then

shipped from the Spansion factory with the Factory Secured Silicon Sector and Customer Secured

Silicon Sector permanently locked. Contact your local representative for details on using Spansion

programming services.

Table 11.1

Addresses

Sector

Sector Size

Address Range

Customer

128 words

000080h-0000FFh

Factory

128 words

000000h-00007Fh

S75WS256NDFBAWMB Datasheet(PDF) 64 Page - SPANSION

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