L200BB55RD AMD [Advanced Micro Devices], L200BB55RD Datasheet - Page 14

• Manufacturer Part Number: L200BB55RD
• Description: 2 Megabit (256 K x 8-Bit/128 K x 16-Bit) CMOS 3.0 Volt-only Boot Sector Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

L = Logic Low = V
Sector Protection/Unprotection
The hardware sector protection feature disables both
program and erase operations in any sector. The hard-
ware sector unprotection feature re-enables both
program and erase operations in previously protected
sectors. Sector protection/unprotection can be imple-
mented via two methods.
The primary method requires V
only, and can be implemented either in-system or via
programming equipment. Figure 1 shows the algo-
rithms and Figure 23 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.
The alternate method intended only for programming
equipment requires V
This method is compatible with programmer routines
written for earlier 3.0 volt-only AMD flash devices. Pub-
12
Manufacturer ID: AMD
Device ID:
Am29LV200B
(Top Boot Block)
Device ID:
Am29LV200B
(Bottom Boot Block)
Sector Protection Verification
Description
IL
, H = Logic High = V
Mode
Word
Word
Byte
Byte
ID
Table 4. Am29LV200B Autoselect Codes (High Voltage Method)
on address pin A9 and OE#.
CE#
L
L
L
L
L
L
ID
on the RESET# pin
OE#
IH
L
L
L
L
L
L
, SA = Sector Address, X = Don’t care.
WE#
H
H
H
H
H
H
A16
A12
SA
D A T A S H E E T
to
X
X
X
Am29LV200B
A11
A10
to
X
X
X
X
V
V
V
V
A9
lication number 21226 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™ Service. Contact an
AMD representative for details.
It is possible to determine whether a sector is protected
or unprotected. See “Autoselect Mode” 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 V
tected sectors can be programmed or erased by
selecting the sector addresses. Once V
from the RESET# pin, all the previously protected
sectors are protected again. Figure 2 shows the algo-
rithm, and Figure 22 shows the timing diagrams, for this
feature.
ID
ID
ID
ID
A8
A7
to
X
X
X
X
A6
L
L
L
L
A5
A2
to
X
X
X
X
ID
. During this mode, formerly pro-
A1
H
L
L
L
A0
H
H
L
L
21521D6 October 10, 2006
DQ15
DQ8
22h
22h
to
X
X
X
X
X
ID
(unprotected)
(protected)
is removed
DQ7
DQ0
3Bh
3Bh
BFh
BFh
01h
01h
00h
to