AM29F400AB-90EC データシートの表示（PDF） - Advanced Micro Devices
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AM29F400AB-90EC
Advanced Micro Devices
AM29F400AB-90EC Datasheet PDF : 35 Pages
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PRELIMINARY
Output Disable
With the OE input at a logic high level (VIH), output from
the device is disabled. This will cause the output pins to
be in a high impedance state.
Autoselect
The autoselect mode allows the reading of a binary
code from the device and will identify its manufacturer
and type. This mode is intended for use by program-
ming equipment for the purpose of automatically
matching the device to be programmed with its corre-
sponding programming algorithm. This mode is func-
tional over the entire temperature range of the device.
To activate this mode, the programming equipment
must force VID (11.5 V to 12.5 V) on address pin A9.
Two identifier bytes may then be sequenced from the
device outputs by toggling address A0 from VIL to VIH.
All addresses are don’t cares except A0, A1, and A6
(see Table 3).
The manufacturer and device codes may also be read
via the command register, for instances when the
Am29F400A is erased or programmed in a system
without access to high voltage on the A9 pin. The com-
mand sequence is illustrated in Table 4 (see Autoselect
Command Sequence).
Byte 0 (A0 = VIL) represents the manufacturer’s code
(AMD=01H) and byte 1 (A0 = VIH) the device identifier
code (Am29F400AT = 23H and Am29F400AB = ABH
for x8 mode; Am29F400AT = 2223H and Am29F400AB
= 22ABH for x16 mode). These two bytes/words are
given in the table below. 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 the Autoselect, A1 must be VIL
(see Tables 3 and 4).
The autoselect mode also facilitates the determination
of sector protection in the system. By performing a read
operation at the address location XX02H with the
higher order address bits A12–A17 set to the desired
sector address, the device will return 01H for a pro-
tected sector and 00H for a non-protected sector.
Table 3. Am29F400A Sector Protection Verify Autoselect Codes
Type
A12-A17
A6
A1
A0
Manufacturer Code-AMD
X
Byte
Am29F400AT
X
Word
Am29F400A Device
Byte
Am29F400AB
X
Word
VIL
VIL
VIL
VIL
VIL
VIH
VIL
VIL
VIH
Sector Protection
Sector
Address
VIL
VIH
VIL
*Outputs 01H at protected sector addresses
Code (HEX)
01H
23H
2223H
ABH
22ABH
01H*
Table 4. Expanded Autoselect Code Table
Type
Code
DQ
15
DQ
14
DQ
13
DQ
12
DQ
11
DQ
10
DQ
9
DQ DQ DQ DQ DQ DQ DQ DQ DQ
8 76543210
Manufacturer Code-AMD
01H 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Am29F400AT(B) 23H A-1 HI-Z HI-Z HI-Z HI-Z HI-Z HI-Z HI-Z 0 0 1 0 0 0 1 1
Am29F400A
(W) 2223H 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 1
Device
Am29F400AB(B) ABH A-1 HI-Z HI-Z HI-Z HI-Z HI-Z HI-Z HI-Z 1 0 1 0 1 0 1 1
(W) 22ABH 0 0 1 0 0 0 1 0 1 0 1 0 1 0 1 1
Sector Protection
01H 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
B) - Byte mode
(W) - Word mode
Am29F400AT/Am29F400AB
9
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