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S29PL127J/S29PL064J/S29PL032J for MCP
S29PL127J_064J_032J_MCP_00_A3 August 12, 2004
A d v a n c e I n f o r m a t i o 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 V
ID
. During this mode, formerly protected sectors can be pro-
grammed or erased by selecting the sector addresses. Once V
ID
is removed from
the RESET# pin, all the previously protected sectors are protected again. 2 shows
the algorithm, and 21 shows the timing diagrams, for this feature. While PPB lock
is set, the device cannot enter the Temporary Sector Unprotection 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. It uses indicator bits (DQ6, DQ7) to indicate the fac-
tory-locked and customer-locked status of the part.
The system accesses the Secured Silicon Sector through a command sequence
(see the Enter Secured Silicon Sector/Exit Secured Silicon Sector Command Se-
quence). After the system has written the Enter Secured Silicon Sector command
sequence, it may read the Secured Silicon Sector by using the addresses nor-
mally occupied by the boot sectors. This mode of operation continues 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 de-
vice reverts to sending commands to the normal address space.
Note that the
ACC function and unlock bypass modes are not available when the Secured Sili-
con Sector is enabled.
Notes:
1. All protected sectors unprotected (If WP#/ACC = V
IL
, upper two and lower two
sectors will remain protected).
2. All previously protected sectors are protected once again
Figure 2.
Temporary Sector Unprotect Operation
START
Perform Erase or
Program Operations
RESET# = V
IH
Temporary Sector
Unprotect Completed
(Note 2)
RESET# = V
ID
(Note 1)