
October 28, 2005 S71PL129Jxx_00_A8
S71PL129JC0/S71PL129JB0/S71PL129JA0
39
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Informatio n
Temporary Sector Unprotect
This feature allows temporary unprotection of previously protected sectors to
change data in-system. The Sector Unprotect mode is activated by setting the
RESET# pin to
VID. During this mode, formerly protected sectors can be pro-
grammed or erased by selecting the sector addresses. Once VID is removed from
the RESET# pin, all the previously protected sectors are protected again.
feature. While PPB lock is set, the device cannot enter the Temporary Sector Un-
protection Mode.
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
128-word Secured Silicon sector is divided into 64 factory-lockable words that
can be programmed and locked by the customer. The Secured Silicon sector is
located at addresses 000000h-00007Fh in both Persistent Protection mode and
Password Protection mode. Indicator bits DQ6 and DQ7 are used to indicate the
factory-locked and customer locked status of the part.
The system accesses the Secured Silicon Sector through a command sequence
Sector command sequence, it may read the Secured Silicon Sector by using the
addresses normally occupied by the boot sectors. This mode of operation contin-
ues until the system issues the Exit Secured 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 the normal address space. Note
that the ACC function and unlock bypass modes are not available when the Se-
cured Silicon Sector is enabled.
Notes:
1. All protected sectors are unprotected (If WP#/ACC = VIL, upper two and lower
two sectors remain protected).
2. All previously protected sectors are protected once again
Figure 2. Temporary Sector Unprotect Operation
START
Perform Erase or
Program Operations
RESET# = VIH
Temporary Sector
Unprotect Completed
(Note 2)
RESET# = VID
(Note 1)