D A T A
Table 4.
S H E E T
Am29F400B Autoselect Codes (High Voltage Method)
A17 A11
to
to
WE# A12 A10
H
H
X
X
H
H
X
X
H
V
ID
X
L
X
L
H
X
X
ABh
01h
(protected)
00h
(unprotected)
V
ID
X
L
X
L
H
X
22h
23h
ABh
X
X
A8
to
A7
X
A5
to
A2
X
DQ8
to
DQ15
X
22h
DQ7
to
DQ0
01h
23h
Description
Mode
CE#
L
L
L
L
L
OE#
L
L
L
L
L
A9
V
ID
A6
L
A1
L
A0
L
Manufacturer ID: AMD
Device ID:
Am29F400B
(Top Boot Block)
Device ID:
Am29F400B
(Bottom Boot Block)
Word
Byte
Word
Byte
Sector Protection Verification
L
L
H
SA
X
V
ID
X
L
X
H
L
X
L = Logic Low = V
IL
, H = Logic High = V
IH
, 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 must be implemented
using programming equipment. The procedure
requires a high voltage (V
ID
) on address pin A9 and
OE#. Details on this method are provided in a supple-
ment, publication number 20185. Contact an AMD
representative to obtain a copy of this document.
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.
rithm, and Figure 18 shows the timing diagrams, for this
feature.
START
RESET# = V
ID
(Note 1)
Perform Erase or
Program Operations
RESET# = V
IH
Temporary Sector
Unprotect Completed
(Note 2)
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
ID
. During this mode, formerly pro-
tected sectors can be programmed or erased by
selecting the sector addresses. Once V
ID
is removed
from the RESET# pin, all the previously protected
sectors are protected again. Figure 1 shows the algo-
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
again.
Figure 1.
Temporary Sector Unprotect Operation
November 1, 2006 21505E5
Am29F400B
11
AMD [ ADVANCED MICRO DEVICES ]
