E S I
I
ES
Excel Semiconductor inc.
be protected prior to the first sector unprotection
write cycle to avoid any over-erase due to the intrin-
sic erase characteristics of the protection cell. After
the unprotection operation, all previously protected
sectors will need to be individually re-protected.
Standard microprocessor bus cycle timings are used
in the unprotection and unprotect verification opera-
tions. Three unprotect methods are provided in the
ES29LV320 device. All unprotection and unprotect
verification cycles are summarized in detail at the
Table 1.
-
In-system unprotection
-
A9 High-voltage unprotection
-
Temporary sector unprotection
If the system asserts V
IL
on the WP#/ACC pin, the
device disables program and erase functions in the
two “outermost” 8Kbytes boot sectors
indepen-
dently of whether those sectors were protected or
unprotected using the method described in “Sector
Group Protection and Unprotection”. The two outer-
most of 8 Kbyte 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 V
IH
on the WP#/ACC pin, the
device reverts to whether the two outermost 8
Kbyte boot sectors were last set to be protected or
unprotected. That is, sector protection or unprotec-
tion for these two sectors depends on whether they
were last protected or unprotected using the
method described in “Sector Group Protection and
Unprotection”.
Note that the WP#/ACC pin must not be left floating
or unconnected; inconsistent behavior of the device
may result.
In-System Unprotection
“In-system unprotection”, the primary method,
requires V
ID
(11.5V~12.5V) on the
RESET#
with
A6=1, A1=1, and A0=0. This method can be imple-
mented either in-system or via programming equip-
ment. This method uses standard microprocessor
bus cycle timing. Refer to Fig. 29 for timing diagram
and Fig. 4 for the unprotection algorithm.
A9 High-Voltage Unprotection
“High-voltage unprotection”, the alternate method
intended only for programming equipment, must
force V
ID
(11.5~12.5V) on address pin
A9
and con-
trol pin
OE#
with A6=1, A1=1 and A0=0. Refer to
Fig. 32 for timing diagram and Fig. 6 for the unpro-
tection algorithm.
START
RESET# = V
ID
(Note 1)
Temporary Sector Unprotect
This feature allows temporary unprotection of previ-
ously protected sectors to change data in-system.
The Sector Unprotect mode is activated by setting
the RESET# pin to V
ID
(11.5V-12.5V). 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 pro-
tected again. Fig. 1 shows the algorithm, and Fig. 27
shows the timing diagrams for this feature.
Perform Erase or
Program Operations
RESET# = V
IH
Temporary Sector
Unprotect Completed
(Note 2)
Notes:
1. All protected sectors are unprotected (If WP#/ACC = V
IL
,
outermost boot sectors will remain protected).
2. All previously protected sectors are protected once again.
WRITE PROTECT ( WP# )
The Write Protect function provides a hardware
method of protecting certain boot sectors without
using V
ID
. This function is one of two provided by the
WP#/ACC pin.
Figure 1. Temporary Sector Unprotect
Operation
9
ES29LV320D
Rev. 2D Jan 5, 2006
EXCELSEMI [ EXCEL SEMICONDUCTOR INC. ]
