AM29LV640MH SPANSION [SPANSION], AM29LV640MH Datasheet - Page 20

• Manufacturer Part Number: AM29LV640MH
• Description: 64 Megabit (4 M x 16-Bit/8 M x 8-Bit) MirrorBit 3.0 Volt-only Uniform Sector Flash Memory with VersatileI/O Control
• Manufacturer: SPANSION [SPANSION]

Write Protect (WP#)
The Write Protect function provides a hardware
method of protecting the first or last sector without
using V
vided by the WP#/ACC input.
If the system asserts V
vice disables program and erase functions in the first
or last sector independently of whether those sectors
were protected or unprotected using the method de-
scribed in “Sector Group Protection and Unprotection”.
Note that if WP#/ACC is at V
the standby mode, the maximum input load current is
increased. See the table in “DC Characteristics”.
If the system asserts V
vice reverts to whether the first or last sector was pre-
viously set to be protected or unprotected using the
method described in “Sector Group Protection and
Notes:
1. All protected sector groups unprotected (If WP# = V
2. All previously protected sector groups are protected once again.
18
ID
. Write Protect is one of two functions pro-
IL
IH
on the WP#/ACC pin, the de-
on the WP#/ACC pin, the de-
Figure 1. Temporary Sector Group Unprotect Operation
IL
when the device is in
D A T A S H E E T
Am29LV640MH/L
Program Operations
Completed (Note 2)
Temporary Sector
Perform Erase or
IL
Group Unprotect
RESET# = V
RESET# = V
, the first or last sector will remain protected).
(Note 1)
START
Unprotection”. Note: No external pullup is necessary
since the WP#/ACC pin has internal pullup to V
Temporary Sector Group Unprotect
(Note: In this device, a sector group consists of four ad-
jacent sectors that are protected or unprotected at the
same time (see
This feature allows temporary unprotection of previ-
ously protected sector groups to change data in-sys-
tem. The Sector Group Unprotect mode is activated by
setting the RESET# pin to
merly protected sector groups can be programmed or
erased by selecting the sector group addresses. Once
V
protected sector groups are protected again. Figure 1
shows the algorithm, and Figure 23 shows the timing
diagrams, for this feature.
ID
ID
IH
is removed from the RESET# pin, all the previously
Table
4).
V
ID
. During this mode, for-
December 14, 2005
CC
.