am49lv128bm Meet Spansion Inc., am49lv128bm Datasheet - Page 22

• Manufacturer Part Number: am49lv128bm
• Description: Stacked Multi-chip Package Mcp ,128 Megabit 8 M ? 16-bit ,uniform Sector Flash Memory And 32 Mbit 2 M ? 16-bit Pseudo-static Ram With Page Mode Featuring Mirrorbit Technology,supplemental Datasheet
• Manufacturer: Meet Spansion Inc.

Write Protect (WP#)
The Write Protect function provides a hardware
method of protecting the last sector without using V
Write Protect is one of two functions provided by the
WP#/ACC input.
If the system asserts V
vice disables program and erase functions in the last
sector independently of whether those sectors were
protected or unprotected using the method described
in “Sector Group Protection and Unprotection”. Note
that if WP#/ACC is at V
standby mode, the maximum input load current is in-
creased. See the table in “DC Characteristics”.
If the system asserts V
vice reverts to whether the last sector was previously
set to be protected or unprotected using the method
described in “Sector Group Protection and Unprotec-
tion”. Note that WP# has an internal pullup; when un-
connected, WP# is at V
Temporary Sector Group Unprotect
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 VID. During this mode, for-
merly protected sector groups can be programmed or
erased by selecting the sector group addresses. Once
V
ously protected sector groups are protected again.
Figure 1 shows the algorithm, and Figure 23 shows
the timing diagrams, for this feature.
20
ID
is removed from the RESET# pin, all the previ-
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on the WP#/ACC pin, the de-
on the WP#/ACC pin, the de-
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.
when the device is in the
Am49LV128BM
ID
.
Notes:
1. All protected sector groups unprotected (If WP# = V
2. All previously protected sector groups are protected
the last sector group will remain protected).
once again.
Figure 1. Temporary Sector Group
Unprotect Operation
Temporary Sector Group
Unprotect Completed
Program Operations
Perform Erase or
RESET# = V
RESET# = V
(Note 1)
(Note 2)
START
ID
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June 17, 2004
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