D A T A S H E E T
The primary method requires VID on the RESET# pin
using the method described in “Sector/Sector Block
Protection and Unprotection” on page 15. The two out-
ermost 8 Kbyte boot sectors are the two sectors
containing the lowest addresses in a bottom-boot-con-
figured device, or the two sectors containing the
highest addresses in a top-boot-configured device.
only, and is implemented either in-system or via pro-
gramming equipment. Figure 1, on page 17 shows the
algorithms and Figure 24, on page 43 shows the timing
diagram. This method uses standard microprocessor
bus cycle timing. For sector unprotect, all unprotected
sectors must first be protected prior to the first sector
unprotect write cycle.
If the system asserts VIH on the WP#/ACC pin, the
device reverts to whether the two outermost 8 Kbyte
boot sectors were last set to be protected 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 described
in “Sector/Sector Block Protection and Unprotection”
on page 15.
The alternate method intended only for programming
equipment requires VID on address pin A9 and OE#.
This method is compatible with programmer routines
written for earlier 3.0 volt-only AMD flash devices. Pub-
lication number 21622 contains further details. Contact
an AMD representative to request the document con-
taining further details.
Note that if the system asserts VHH on the WP#/ACC
pin, all sectors, including the two outermost sectors,
are unprotected. VHH is intended for accelerated in-
system programming of the device during system pro-
duction. It is advisable, therefore, not to assert VHH on
this pin after the system has been placed in the field for
use. If faster programming is desired, the system may
use the unlock bypass program command sequence.
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 protected
or unprotected. See “Autoselect Mode” on page 14 for
details.
Temporary Sector Unprotect
This feature allows temporary unprotection of previ-
ously protected sectors to change data in-system. The
Sector Unprotect mode is activated by setting the
RESET# pin to VID. During this mode, formerly pro-
tected sectors can be programmed or erased by
selecting the sector addresses. Once VID is removed
from the RESET# pin, all the previously protected
sectors are protected again. Figure 2, on page 18
shows the algorithm, and Figure 22, on page 42 shows
the timing diagrams, for this feature.
Write Protect (WP#)
The write protect function provides a hardware method
of protecting certain boot sectors without using VID.
This function is one of two provided by the WP#/ACC
pin.
If the system asserts VIL on the WP#/ACC pin, the
device disables program and erase functions in the two
“outermost” 8 Kbyte boot sectors independently of
whether those sectors were protected or unprotected
16
Am29SL160C
21635C5 January 23, 2007
AMD [ AMD ]
