![](http://datasheet.mmic.net.cn/170000/S71PL191HB0BFI100_datasheet_9723326/S71PL191HB0BFI100_55.png)
May 7, 2004 S29PL127H_129H_00A1
S29PL127H/S29PL129H
39
Pre l i m i n a r y
a hardware reset, the device reverts to sending 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 Area (64 words)
The factory-locked area of the SecSi Sector (000000h-00003Fh) is locked when
the part is shipped, whether or not the area was programmed at the factory. The
SecSi Sector Factory-locked Indicator Bit (DQ7) is permanently set to a “1”. Op-
tional Spansion programming services can program the factory-locked area with
a random ESN, a customer-defined code, or any combination of the two. Because
only the factory can program and protect the factory-locked area, this method
ensures the security of the ESN once the product is shipped to the field. Contact
the local sales office for details on using Spansion programming services.
Customer-Lockable Area (64 words)
The customer-lockable area of the SecSi Sector (000040h-00007Fh) is shipped
unprotected, which allows the customer to program and optionally lock the area
as appropriate for the application. The SecSi Sector Customer-locked Indicator
Bit (DQ6) is shipped as “0” and can be permanently locked to “1” by issuing the
SecSi Protection Bit Program Command. The SecSi Sector can be read any num-
ber 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 SecSi Sector.
The Customer-lockable SecSi Sector area can be protected using one of the
following procedures:
Follow the SecSi Sector protection Agorithm as shown in
Figure 3. This allows
in-system protection of the SecSi Sector without raising any device pin to a
high voltage. Note that this method is only applicable to the SecSi Sector.