am42dl1612d Meet Spansion Inc., am42dl1612d Datasheet - Page 83

• Manufacturer Part Number: am42dl1612d
• Description: 16 Mbit 2 M ? 8-bit/1 M ? 16-bit Cmos And 2 Mbit 128 K ? 16-bit Static Ram Preliminary
• Manufacturer: Meet Spansion Inc.

The device is shipped with all sectors unprotected.
It is possible to determine whether a sector is pro-
tected or unprotected. See the Autoselect Mode
section for details.
Write Protect (WP#)
The Write Protect function provides a hardware
method of protecting certain boot sectors without
using V
WP#/ACC pin.
If the system asserts V
vice 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 in “Sector/Sector Block
Protection and Unprotection”. The two outermost 8
Kbyte boot sectors are the two sectors containing the
lowest addresses in a top-boot-configured device, or
the two sectors containing the highest addresses in a
top-boot-configured device.
If the system asserts V
vice reverts to whether the two outermost 8 Kbyte 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 “Sec-
tor/Sector Block Protection and Unprotection”.
Note that the WP#/ACC pin must not be left floating or
unconnected; inconsistent behavior of the device may
result.
Temporary Sector/Sector Block 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
protected or unprotected at the same time (see Tables
8 and 9).
18
ID
. This function is one of two provided by the
IL
IH
on the WP#/ACC pin, the de-
on the WP#/ACC pin, the de-
Am42DL16x2D
This feature allows temporary unprotection of previ-
ously protected sectors to change data in-system. The
Sector Unprotect mode is activated by setting the RE-
SET# pin to V
formerly protected sectors can be programmed or
erased by selecting the sector addresses. Once V
removed from the RESET# pin, all the previously pro-
tected sectors are protected again. Figure 1 shows the
algorithm, and Figure 25 shows the timing diagrams,
for this feature.
Notes:
1. All protected sectors unprotected (If WP#/ACC = V
2. All previously protected sectors are protected once
Figure 1. Temporary Sector Unprotect Operation
outermost boot sectors will remain protected).
again.
ID
(8.5 V – 12.5 V). During this mode,
Unprotect Completed
Program Operations
Temporary Sector
Perform Erase or
RESET# = V
RESET# = V
(Note 1)
(Note 2)
START
ID
IH
February 6, 2004
IL
ID
,
is