AM29LV004B-150EEB AMD [Advanced Micro Devices], AM29LV004B-150EEB Datasheet - Page 10

• Manufacturer Part Number: AM29LV004B-150EEB
• Description: 4 Megabit (512 K x 8-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 pro-
gram and erase operations in previously protected
sectors.
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.
Sector protection/unprotection must be implemented
using programming equipment.The procedure requires
a high voltage (V
tails on this method are provided in a supplement, pub-
lication number 20874. Contact an AMD representative
to request a copy.
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 RE-
SET# pin to V
sectors can be programmed or erased by selecting the
sector addresses. Once V
10
Manufacturer ID: AMD
Device ID: Am29LV004T
(Top Boot Block)
Device ID: Am29LV004B
(Bottom Boot Block)
Sector Protection Verification
Description
ID
. During this mode, formerly protected
ID
IL
) on address pin A9 and OE#. De-
, H = Logic High = V
Table 4. Am29LV004 Autoselect Codes (High Voltage Method)
ID
is removed from the RE-
CE#
L
L
L
L
IH
, SA = Sector Address, X = Don’t care.
OE#
P R E L I M I N A R Y
L
L
L
L
WE#
H
H
H
H
Am29LV004
A18
A13
SA
to
X
X
X
SET# pin, all the previously protected sectors are
protected again. Figure 1 shows the algorithm, and
Figure 19 shows the timing diagrams, for this feature.
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
Figure 1. Temporary Sector Unprotect Operation
A12
A10
to
X
X
X
X
again.
V
V
V
V
A9
ID
ID
ID
ID
A8
A7
to
X
X
X
X
A6
L
L
L
L
Unprotect Completed
Program Operations
Temporary Sector
Perform Erase or
RESET# = V
RESET# = V
A5
A2
to
X
X
X
X
(Note 1)
(Note 2)
START
A1
H
L
L
L
ID
IH
A0
H
H
L
L
(unprotected)
(protected)
DQ7
DQ0
01h
B5h
B6h
01h
00h
21522A-4
to