D A T A S H E E T
Table 4. Am29SL400C Autoselect Codes (High Voltage Method)
A17t A11
to
WE# A12 A10
A8
to
A7
A5
to
A2
DQ8
to
DQ15
DQ7
to
DQ0
o
Description
Mode
CE#
L
OE#
A9
A6
A1
A0
Manufacturer ID: AMD
L
L
H
H
X
X
X
VID
X
X
L
X
X
L
L
X
01h
70h
Device ID:
Am29SL400C
(Top Boot Block)
Word
Byte
Word
Byte
L
22h
X
VID
L
L
L
L
H
H
L
L
L
L
L
L
H
H
H
X
22h
X
70h
F1h
Device ID:
Am29SL400C
(Bottom Boot Block)
X
X
X
VID
X
X
X
X
F1h
X
01h (protected)
Sector Protection Verification
L
L
H
SA
VID
L
H
L
00h
(unprotected)
X
L = Logic Low = VIL, H = Logic High = VIH, SA = Sector Address, X = Don’t care.
factory prior to shipping the device through AMD’s Express-
Flash™ Service. Contact an AMD representative for details.
Sector Protection/Unprotection
The hardware sector protection feature disables both pro-
gram and erase operations in any sector. The hardware sec-
tor unprotection feature re-enables both program and erase
operations in previously protected sectors. Sector protec-
tion/unprotection can be implemented via two methods.
It is possible to determine whether a sector is protected or
unprotected. See Autoselect Mode‚ on page 11 for details.
Temporary Sector Unprotect
This feature allows temporary unprotection of previously pro-
tected sectors to change data in-system. The Sector Unpro-
tect mode is activated by setting the RESET# pin to VID.
During this mode, formerly protected sectors can be pro-
grammed 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 3‚ on page 16
shows the algorithm, and Figure 22 shows the timing dia-
grams, for this feature.
Sector protection/unprotection requires VID on the RESET#
pin only, and can be implemented either in-system or via
programming equipment. Figure 2‚ on page 14 shows the al-
gorithms and Figure 24‚ on page 37 shows the timing dia-
gram. 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 cy-
cle.
The device is shipped with all sectors unprotected. AMD of-
fers the option of programming and protecting sectors at its
12
Am29SL400C
Am29SL400C_00_A6 January 23, 2007
AMD [ AMD ]
