18 Am29DL320G
The alter nate method intend ed only for programming
equipment requires V
ID
on address pin A9 and OE #.
This method is compatible with programmer routines
written for earlier 3.0 volt-only AMD flash devices.
Publication number 22244 contains further details;
contact an AMD representative to request a copy.
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™ Ser vice. Contact an
AMD representative for details.
It is possible to determine whether a sector is pro-
tected or unpro tected. See the Autoselect Mode sec-
tion for details.
Write Protect (WP#)
The Write Protect function provides a hardware
method of protecting cer tain boot sectors without
using V
ID
. This function is on e 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 metho d described in “Sector/Se ctor 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 8K Byte
boot sectors were last set to be protecte d or unpro-
tected. That is, sector protection or unprotection for
these two sectors depends on whether they were last
protected or unprotected using the method descr ibed
in “Sector/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 Unprotect
(Note: For the following discussion, the term “sector”
applies to both sectors and sector blocks. A sector
block consists of two o r more adjace nt s ectors that are
protected or unprotected at the same time (Tables 2
and 4).
This feature allows temporar y unprotection of prev i-
ously protected sectors to change data in-system. The
Sector Unprotect mode is activated by setting the RE-
SET# pin to V
ID
. During th is mode, for mer ly protected
sectors can be progr ammed or er ased b y sele cting the
sector addresses. Once V
ID
is removed from the RE-
SET# pin, all the previously protected sectors are
protected again. Figure 1 shows the algorithm, and
Figure 25 shows the timing diagrams, for this feature.
Figure 1. Temporary Sector Unprotect Operation
START
Perform Erase or
Program Operations
RESET# = V
IH
Temporar y 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 pro tec ted once
again.
