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the Address Inputs and pulsing Latch Enable Low,
VIL. The Address Inputs are latched by the Com-
mand Interface on the rising edge of Latch Enable,
Write Enable or Chip Enable, whichever occurs
first. Commands and Input Data are latched on the
rising edge of Chip Enable, E, or Write Enable, W,
whichever occurs first. Output Enable must remain
High, and Output Disable Low, during the whole
Asynchronous Bus Write operation.
See Figure
13, Asynchronous Latch Controlled
Write AC Waveforms, and Table
19, Asynchro-
nous Write and Latch Controlled Write AC Charac-
teristics, for details of the timing requirements.
Output Disable. The data outputs are high im-
pedance when the Output Enable, G, is at VIH or
Output Disable, GD, is at VIL.
Standby. When Chip Enable is High, VIH, and the
Program/Erase Controller is idle, the memory en-
ters Standby mode, the power consumption is re-
duced to the standby level and the Data Inputs/
Outputs pins are placed in the high impedance
state regardless of Output Enable, Write Enable or
Output Disable inputs.
Automatic Low Power. If there is no change in
the state of the bus for a short period of time during
Asynchronous Bus Read operations the memory
enters Auto Low Power mode where the internal
Supply Current is reduced to the Auto-Standby
Supply Current. The Data Inputs/Outputs will still
output data if a Bus Read operation is in progress.
Automatic Low Power is only available in Asyn-
chronous Read modes.
Power-Down. The memory is in Power-down
when Reset/Power-Down, RP, is at VIL. The pow-
er consumption is reduced to the power-down lev-
el
and
the
outputs
are
high
impedance,
independent of the Chip Enable, E, Output Enable,
G, Output Disable, GD, or Write Enable, W, inputs.
Electronic Signature. Two codes identifying the
manufacturer and the device can be read from the
memory allowing programming equipment or ap-
plications to automatically match their interface to
the characteristics of the memory. The Electronic
Signature is output by giving the Read Electronic
Signature command. The manufacturer code is
output when all the Address inputs are at VIL. The
device code is output when A1 is at VIH and all the
other address pins are at VIL. See Table 5. Issue a Read Memory Array command to return to Read
mode.
Table 4. Asynchronous Bus Operations
Note: X = Don’t Care
Bus Operation
Step
E
G
GD
W
RP
L
A0-A18
DQ0-DQ31
Asynchronous Bus Read
VIL
VIH
VIL
Address
Data Output
Asynchronous Latch
Controlled Bus Read
Address Latch
VIL
VIH
VIL
VIH
VIL
Address
High Z
Read
VIL
VIH
X
Data Output
Asynchronous Page
Read
VIL
VIH
X
Address
Data Output
Asynchronous Bus Write
VIL
VIH
X
VIL
VIH
VIL
Address
Data Input
Asynchronous Latch
Controlled Bus Write
Address Latch
VIL
VIH
VIL
Address
High Z
Write
VIL
VIH
X
VIL
VIH
X
Data Input
Output Disable, G
VIL
VIH
X
High Z
Output Disable, GD
VIL
VIH
X
High Z
Standby
VIH
XX
X
VIH
X
High Z
Reset/Power-Down
X
VIL
X
High Z