March 10, 2005 S29JL032H_00A11
S29JL032H
23
Ad vance
Info rmat i o n
Write Protect (WP#)
The Write Protect function provides a hardware method of protecting certain boot
sectors without using VID. This function is one of two provided by the WP#/ACC
pin.
If the system asserts VIL on the WP#/ACC pin, the device disables program and
erase functions in the two outermost 8 Kbyte boot sectors independently of
whether those sectors were protected or unprotected using the method described
boot sectors are the two sectors containing the lowest addresses in a bottom-
boot-configured device, or the two sectors containing the highest addresses in a
top-boot-configured device.
If the system asserts VIH on the WP#/ACC pin, the device reverts to whether the
two outermost 8K Byte boot sectors were last set to be protected or unprotected.
That is, sector protection or unprotection for these two 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.
Table 8. WP#/ACC Modes
Temporary Sector Unprotect
(Note: For the following discussion, the term “sector” applies to both sectors and
sector blocks. A sector block consists of two or more adjacent sectors that are
This feature allows temporary unprotection of previously protected sectors to
change data in-system. The Temporary Sector Unprotect mode is activated by
setting the RESET# pin to
VID. During this mode, formerly protected sectors can
be programmed or erased by selecting the sector addresses. Once VID is removed
from the RESET# pin, all the previously protected sectors are protected again.
feature. If the WP#/ACC pin is at VIL, the two outermost boot sectors will remain
protected during the Temporary sector Unprotect mode.
WP# Input Voltage
Device
Mode
VIL
Disables programming and erasing in the two outermost boot sectors
VIH
Enables programming and erasing in the two outermost boot sectors, dependent on
whether they were last protected or unprotected
VHH