P R E L I M I N A R Y
Autoselect
The Autoselect mode allows the reading out of a binary
code from the device and will identify its manufacturer
and type. The intent is to allow programming equipment
to automatically match the device to be programmed
with its corresponding programming algorithm. The Au-
toselect command may also be used to check the sta-
tus of write-protected sectors (see Table 2). This mode
is functional over the entire temperature range of the
device.
To activate this mode, the programming equipment
must force V
ID
(12.0 V
±
5%) on address pin A9. Two
identifier bytes may then be sequenced from the device
outputs by toggling address A0 from V
IL
to V
IH
. All ad-
dresses are don’t cares except A0, A1, and A6 see
Table 2.
The manufacturer and device codes may also be read
via the command register, for instances when the
Am29LV008 is erased or programmed in a system with-
out access to high voltage on the A9 pin. The command
sequence is illustrated in Table 5 on page 13.
3.0 V-only Flash
Byte 0 (A0 = V
IL
) represents the manufacturer’s code
and byte 1 (A0 = V
IH
) the device identifier code. For the
Am29LV008 these two bytes are given in Table 2. All
identifiers for manufacturer and device will exhibit odd
parity with DQ7 defined as the parity bit. In order to
read the proper device codes when executing Autose-
lect, A1 must be V
IL
(see Table 2). The device code is
3EH (for top boot block) or 37H (for bottom boot block).
In order to determine which sectors are write protected,
A1 must be at V
IH
while running through the sector ad-
dresses; if the selected sector is protected, a logical ‘1’
will be output on DQ0 (DQ0 = 1).
Table 2.
Type
Manufacturer Code: AMD
29LV008 Device
(Top Boot Block)
29LV008 Device
(Bottom Boot Block)
Sector Protection
A13–A19
X
X
X
Set Sector
Addresses
A6
L
L
L
L
Autoselect/Sector Protection Codes
A1
L
L
L
H
A0
L
H
H
L
Code
(HEX)
01H
3EH
37H
01H*
DQ
7
0
0
0
0
DQ
6
0
0
0
0
DQ
5
0
1
1
0
DQ
4
0
1
1
0
DQ
3
0
1
0
0
DQ
2
0
1
1
0
DQ
1
0
1
1
0
DQ
0
1
0
1
1
X = Don’t care.
* Outputs 01H at protected sector addresses.
Am29LV008T/Am29LV008B
9
CYPRESS [ CYPRESS SEMICONDUCTOR ]
