March 3, 2009 21526D5
Am29F200B
11
D A TA
SH EE T
Table 4.
Am29F200B 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 must be implemented
using programming equipment. The procedure
requires a high voltage (VID) on address pin A9 and the
control pins. Details on this method are provided in a
supplement, publication number 20551. Contact an
AMD representative to obtain a copy of the appropriate
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
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
1 shows the algo-
rithm, and the Temporary Sector Unprotect diagram
feature.
Figure 1.
Temporary Sector Unprotect Operation
Hardware Data Protection
The command sequence requirement of unlock cycles
for programming or erasing provides data protection
against inadvertent writes (refer to the Command Defi-
nitions table). In addition, the following hardware data
protection measures prevent accidental erasure or pro-
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
XL
X
L
X
01h
Device ID:
Am29F200B
(Top Boot Block)
Word
L
H
XX
VID
XL
X
L
H
22h
51h
Byte
L
H
X
51h
Device ID:
Am29F200B
(Bottom Boot Block)
Word
L
H
XX
VID
XL
X
L
H
22h
57h
Byte
L
H
X
57h
Sector Protection Verification
L
H
SA
X
VID
XL
X
H
L
X
01h
(protected)
X
00h
(unprotected)
START
Perform Erase or
Program Operations
RESET# = VIH
Temporary Sector
Unprotect
Completed (Note 2)
RESET# = VID
(Note 1)
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
again.