Am29DS163D
17
A D V A N C E I N F O R M A T I O N
The alternate method intended only for programming
equipment requires V
ID
on address pin A9 and OE#.
This method is compatible with programmer routines
written for earlier 1.8 volt-only AMD flash devices.
Contact an AMD representative for further details.
The device is shipped with all sectors unprotected.
AMD offers the option of programming and protecting
sectors at its factory prior to shipping the device
through AMD’s ExpressFlash Service. Contact an
AMD representative for details.
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
ID
. This function is one of two provided by the
WP#/ACC pin.
If the system asserts V
IL
on the WP#/ACC pin, the de-
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 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 de-
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).
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
ID
(9.0 – 11.0 V). During this mode,
formerly protected sectors can be programmed or
erased by selecting the sector addresses. Once V
ID
is
removed from the RESET# pin, all the previously pro-
tected sectors are protected again. Figure 1 shows the
algorithm, and Figure 24 shows the timing diagrams,
for this feature.
Figure 1. Temporary Sector Unprotect Operation
START
Perform Erase or
Program Operations
RESET# = V
IH
Temporary Sector
Unprotect Completed
(Note 2)
RESET# = V
ID
(Note 1)
Notes:
1. All protected sectors unprotected (If WP#/ACC = V
IL
,
outermost boot sectors will remain protected).
2. All previously protected sectors are protected once
again.