P R E L I M I N A R Y
Table 4. Am29DL800B Autoselect Codes (High Voltage Method)
A18 A11
to to
Mode CE# OE# WE# A12 A10 A9
A8
to
A7
A5
to
A2
DQ8
to
DQ15
DQ7
to
DQ0
Description
A6
A1
A0
Manufacturer ID: AMD
L
L
L
L
H
H
BA
X
V
X
L
X
L
L
X
01h
4Ah
ID
Device ID:
Am29DL800B
(Top Boot Block)
Word
Byte
Word
Byte
22h
BA
X
V
X
L
L
X
L
L
H
H
ID
L
L
L
L
L
L
H
H
H
X
22h
X
4Ah
CBh
CBh
Device ID:
Am29DL800B
(Bottom Boot Block)
BA
SA
X
X
V
V
X
X
X
X
ID
01h
(protected)
X
X
Sector Protection Verification
L
L
H
L
H
L
ID
00h
(unprotected)
Note: L = Logic Low = V , H = Logic High = V , BA = Bank Address, SA = Sector Address, X = Don’t care.
IL
IH
SET# pin to VID (11.5 V – 12.5 V). During this mode,
formerly protected sectors can be programmed or
erased by selecting the sector addresses. Once VID is
removed from the RESET# pin, all the previously pro-
tected sectors are protected again. Figure 1 shows the
algorithm, and Figure 23 shows the timing diagrams,
for this feature.
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. 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 2 shows the algo-
rithms and Figure 24 shows the timing diagram. This
method uses standard microprocessor bus cycle tim-
ing. For sector unprotect, all unprotected sectors must
first be protected prior to the first sector unprotect write
cycle.
START
RESET# = V
ID
(Note 1)
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 21467 contains further details; contact
an AMD representative to request a copy.
Perform Erase or
Program Operations
RESET# = V
IH
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.
Temporary Sector
Unprotect Completed
(Note 2)
It is possible to determine whether a sector is protected
or unprotected. See the Autoselect Mode section for
details.
21519A-5
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
again.
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-
Figure 1. Temporary Sector Unprotect Operation
Am29DL800B
13
AMD [ AMD ]
