
10
Am29LV200B
Table 4.
Am29LV200B Autoselect Codes (High Voltage Method)
L = Logic Low = VIL, H = Logic High = VIH, SA = Sector Address, X = Don’t care.
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 VID on the RESET# pin
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 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 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 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 shows the algo-
rithm, and Figure 22 shows the timing diagrams, for
this feature.
Description
Mode
CE#
OE#
WE#
A16
to
A12
A11
to
A10
A9
A8
to
A7
A6
A5
to
A2
A1
A0
DQ8
to
DQ15
DQ7
to
DQ0
Manufacturer ID: AMD
L
H
X
VID
XLX
L
X
01h
Device ID:
Am29LV200B
(Top Boot Block)
Word
L
H
XX
VID
XLX
L
H
22h
3Bh
Byte
L
H
X
3Bh
Device ID:
Am29LV200B
(Bottom Boot Block)
Word
L
H
XX
VID
XLX
L
H
22h
BFh
Byte
L
H
X
BFh
Sector Protection Verification
L
H
SA
X
VID
XLX
H
L
X
01h
(protected)
X
00h
(unprotected)