D A T A S H E E T
Table 4. In addition, when verifying sector protection,
Autoselect Mode
the sector address must appear on the appropriate
highest order address bits (see Tables 2 and 3). Table
4 shows the remaining address bits that are don’t
care. When all necessary bits have been set as re-
quired, the programming equipment may then read the
corresponding identifier code on DQ7–DQ0.
The autoselect mode provides manufacturer and de-
vice identification, and sector protection verification,
through identifier codes output on DQ7–DQ0. This
mode is primarily intended for programming equip-
ment to automatically match a device to be pro-
grammed with its corresponding programming
algorithm. However, the autoselect codes can also be
accessed in-system through the command register.
To access the autoselect codes in-system, the host
system can issue the autoselect command via the
command register, as shown in Table 5. This method
does not require VID. See “Command Definitions” for
details on using the autoselect mode.
When using programming equipment, the autoselect
mode requires VID (11.5 V to 12.5 V) on address pin
A9. Address pins A6, A1, and A0 must be as shown in
Table 4. Am29LV400B Autoselect Codes (High Voltage Method)
A17 A11
to to
Mode CE# OE# WE# A12 A10 A9
A8
to
A7
A5
to
A2
DQ8
to
A0 DQ15
DQ7
to
DQ0
Description
A6
A1
Manufacturer ID: AMD
L
L
L
L
H
H
X
X
VID
X
X
L
X
X
L
L
X
01h
B9h
Device ID:
Am29LV400B
(Top Boot Block)
Word
Byte
Word
Byte
22h
X
X
VID
L
L
L
L
H
L
L
L
L
L
L
H
H
H
X
22h
X
B9h
BAh
BAh
Device ID:
Am29LV400B
(Bottom Boot Block)
X
X
X
VID
X
X
X
X
H
L
01h
(protected)
X
X
Sector Protection Verification
L
L
H
SA
VID
L
H
00h
(unprotected)
L = Logic Low = VIL, H = Logic High = VIH, SA = Sector Address, X = Don’t care.
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.
Publication number 20873 contains further details;
contact an AMD representative to request a copy.
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 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.
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 tim-
ing. For sector unprotect, all unprotected sectors must
first be protected prior to the first sector unprotect
write cycle.
It is possible to determine whether a sector is pro-
tected or unprotected. See “Autoselect Mode” for de-
tails.
12
Am29LV400B
21523D4 December 4, 2006
SPANSION [ SPANSION ]
