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May 21, 2004 S29PL127_064_032J_00_A1
S29PL127J/S29PL064J/S29PL032J for MCP
53
Prelimin ary
Write Protect (WP#)
The Write Protect feature provides a hardware method of protecting the upper
two and lower two sectors(PL127J: 0, 1, 268, and 269, PL064J: 0, 1, 140, and
141, PL032J: 0, 1, 76, and 77, PL129J: SA1-133, SA1-134,SA2-0 and SA2-1)
without using VID. This function is provided by the WP# pin and overrides the pre-
If the system asserts VIL on the WP#/ACC pin, the device disables program and
erase functions in the two outermost 4 Kword sectors on both ends of the Flash
array independent of whether it was previously protected or unprotected.
If the system asserts VIH on the WP#/ACC pin, the device reverts the upper two
and lower two sectors to whether they were last set to be protected or unpro-
tected. That is, sector protection or unprotection for these sectors depends on
whether they were last protected or unprotected using the method described in
Note that the WP#/ACC pin must not be left floating or unconnected; inconsistent
behavior of the device may result.
Persistent Protection Bit Lock
The Persistent Protection Bit (PPB) Lock is a volatile bit that reflects the state of
the Password Mode Locking Bit after power-up reset. If the Password Mode Lock
Bit is also set after a hardware reset (RESET# asserted) or a power-up reset, the
ONLY means for clearing the PPB Lock Bit in Password Protection Mode is to issue
the Password Unlock command. Successful execution of the Password Unlock
command clears the PPB Lock Bit, allowing for sector PPBs modifications. Assert-
ing RESET#, taking the device through a power-on reset, or issuing the PPB Lock
Bit Set command sets the PPB Lock Bit to a “1” when the Password Mode Lock Bit
is not set.
If the Password Mode Locking Bit is not set, including Persistent Protection Mode,
the PPB Lock Bit is cleared after power-up or hardware reset. The PPB Lock Bit is
set by issuing the PPB Lock Bit Set command. Once set the only means for clear-
ing the PPB Lock Bit is by issuing a hardware or power-up reset. The Password
Unlock command is ignored in Persistent Protection Mode.
High Voltage Sector Protection
Sector protection and unprotection may also be implemented using programming
equipment. The procedure requires high voltage (VID) to be placed on the RE-
SET# pin. Refer to
Figure 1 for details on this procedure. Note that for sector
unprotect, all unprotected sectors must first be protected prior to the first sector
write cycle.