1. It permanently sets the device to operate using the
Password Protection Mode. It is not possible to re-
verse this function.
during the entire program or erase operation of the two
outermost sectors in the 75% bank.
SecSi™ (Secured Silicon) Sector
Protection
2. It also disables all further commands to the pass-
word region. All program, and read operations are
ignored.
The SecSi Sector is a 256-byte flash memory area
that is either programmable at the customer or by
AMD at the request of the customer. The SecSi Sector
Entry command enables the host system to address
the SecSi Sector for programming or reading. The
SecSi sector address range is 00000h–0003Fh for the
top bootblock configuration and 7FFC0h–7FFFFh for
the bottom bootblock configuration. Address range
00040h–007FFh for the top bootblock and
7F800h–7FFBFh return invalid data when addressed
with the SecSi sector enabled.
Both of these objectives are important, and if not care-
fully considered, may lead to unrecoverable errors.
The user must be sure that the Password Protection
method is desired when setting the Password Mode
Locking Bit. More importantly, the user must be sure
that the password is correct when the Password Mode
Locking Bit is set. Due to the fact that read operations
are disabled, there is no means to verify what the
password is afterwards. If the password is lost after
setting the Password Mode Locking Bit, there will be
no way to clear the PPB Lock bit.
Unlike previous flash memory devices, the
Am29BDD160 allows simultaneous operation while
the SecSi sector is enabled. However, there are a
number of restrictions associated with simultaneous
operation and device operation when the SecSi sector
is enabled:
The Password Mode Locking Bit, once set, prevents
reading the 64-bit password on the DQ bus and further
password programming. The Password Mode Locking
Bit is not erasable. Once Password Mode Locking Bit
is programmed, the Persistent Sector Protection Lock-
ing Bit is disabled from programming, guaranteeing
that no changes to the protection scheme are allowed.
1. The SecSi sector is not available for reading while
the Password Unlock, any PPB program/erase op-
eration, or Password programming are in progress.
Reading to any location in the small (25%) sector
will return the status of these operations until these
operations have completed execution.
64-bit Password
The 64-bit Password is located in its own memory
space and is accessible through the use of the Pass-
word Program and Verify commands (see Password
Verify Command). The password function works in
conjunction with the Password Mode Locking Bit,
which when set, prevents the Password Verify com-
mand from reading the contents of the password on
the pins of the device.
2. Writing the corresponding DYB associated with the
overlaid bootblock sector results in the DYB NOT
being updated. This is only accomplished when the
SecSi sector is not enabled.
3. Reading the corresponding DYB associated with
the overlaid bootblock sector results in reading in-
valid data when the PPB Lock/DYB Verify com-
mand is issued. This function is only accomplished
when the SecSi sector is not enabled.
Write Protect (WP#)
The device features a hardware protection option
using a write protect pin that prevents programming or
erasing, regardless of the state of the sector’s Persis-
tent or Dynamic Protection Bits. The WP# pin is asso-
ciated with the two outermost 8Kbytes sectors in the
75% bank. The WP# pin has no effect on any other
sector. When WP# is taken to VIL, programming and
erase operations of the two outermost 8 Kbytes sec-
tors in the 75% bank are disabled. By taking WP#
back to VIH, the two outermost 8 Kbytes sectors are
enabled for program and erase operations, depending
upon the status of the individual sector Persistent or
Dynamic Protection Bits. If either of the two outermost
sectors Persistent or Dynamic Protection Bits are pro-
grammed, program or erase operations are inhibited.
If the sector Persistent or Dynamic Protection Bits are
both erased, the two sectors are available for pro-
gramming or erasing as long as WP# remains at VIH.
The user must hold the WP# pin at either VIH or VIL
4. All commands are available for execution when the
SecSi sector is enabled except the following list. Is-
suing the following commands while the SecSi sec-
tor is enabled results in the command being
ignored.
■ All Unlock Bypass commands
■ CFI
■ Accelerated Program
■ Program and Sector Erase Suspend
■ Program and Sector Erase Resume
5. Executing the Sector Erase command is permitted
when the SecSi sector is enabled, however, there is
no provision for erasing the SecSi sector with the
Sector Erase command, regardless of the protec-
tion status. The Sector Erase command will erase
all other sectors when the SecSi sector is enabled.
June 7, 2006
Am29BDD160G
27
SPANSION [ SPANSION ]
