AM29BDD160G AMD [Advanced Micro Devices], AM29BDD160G Datasheet - Page 27

• Manufacturer Part Number: AM29BDD160G
• Description: 16 Megabit (1 M x 16-bit/512 K x 32-Bit), CMOS 2.5 Volt-only Burst Mode, Dual Boot, Simultaneous Read/Write Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

The Password Mode Locking Bit, once set, prevents
reading the 64-bit password on the DQ bus and fur-
ther password programming. The Password Mode
Locking Bit is not erasable. Once Password Mode
Locking Bit is programmed, the Persistent Sector
Protection Locking Bit is disabled from programming,
guaranteeing that no changes to the protection
scheme are allowed.
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
Verify
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.
Write Protect (WP#)
The device features a hardware protection op-
tion using a write protect pin that prevents
programming or erasing, regardless of the
state of the sector’s Persistent or Dynamic Pro-
tection Bits. The WP# pin is associated 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 V
and erase operations of the two outermost 8
Kbytes sectors in the 75% bank are disabled.
By taking WP# back to V
Kbytes sectors are enabled for program and
erase operations, depending upon the status of
the individual sector Persistent or Dynamic Pro-
tection Bits. If either of the two outermost
sectors Persistent or Dynamic Protection Bits
are programmed, program or erase operations
are inhibited. If the sector Persistent or Dy-
namic Protection Bits are both erased, the two
sectors are available for programming or eras-
ing as long as WP# remains at V
must hold the WP# pin at either V
the entire program or erase operation of the
two outermost sectors in the 75% bank.
SecSi™ (Secured Silicon) Sector Protection
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 Sec-
tor Entry command enables the host system to
address the SecSi Sector for programming or read-
ing. The SecSi sector address range is 00000h–
0003Fh for the top boot block configuration and
7FFC0h–7FFFFh for the bottom boot block configura-
tion. Address range 00 040 h–00 7F F h for t he top
boot block and 7F800h–7FFBFh return invalid data
when addressed with the SecSi sector enabled.
U n l i k e p r e v i o u s f l a s h m e m o r y d e v i c e s , t h e
Am29BDD160 allows simultaneous operation while
the SecSi sector is enabled. However, there are a
Command). The password function works in
IH
, the two outermost 8
IL
, programming
IH
IH
or V
. The user
Password
IL
during
Am29BDD160G
number of restrictions associated with simultaneous
operation and device operation when the SecSi sec-
tor is enabled:
SecSi Sector Protection Bit
The SecSi Sector Protection Bit prevents program-
ming of the SecSi sector memory area. Once set, the
SecSi sector memory area contents are non-modifi-
able.
The SecSi sector is not available for reading while
the Password Unlock, any PPB program/erase op-
era tio n, or Pa ss wo rd pr og ra m mi n g a r e i n
progress. Reading to any location in the small
(25%) sector will return the status of these oper-
ations until these operations have completed exe-
cution.
Writing the corresponding DYB associated with the
overlaid boot block sector results in the DYB NOT
being updated. This is only accomplished when the
SecSi sector is not enabled.
Reading the corresponding DYB associated with
the overlaid boot block 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.
All commands are available for execution when
the SecSi sector is enabled except the following
list. Issuing the following commands while the
SecSi sector 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
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 pro-
tection status. The Sector Erase command will
erase all other sectors when the SecSi sector is
enabled.
Executing the Chip Erase command is permitted
when the SecSi sector is enabled. The Chip Erase
command erases all sectors in the memory array
except for sector 0 in top-boot block configuration
and sector 45 in bottom-boot block configuration.
The SecSi Sector is a one-time programmable
memory area that cannot be erased.
Executing the SecSi Sector Entry command during
program or erase suspend mode is allowed. The
Sector Erase/Program Resume command is dis-
abled while the SecSi sector is enabled, and the
user cannot resume programming of the memory
array until the Exit SecSi Sector command is writ-
ten.
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