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Mode
CE
L
OE
L
WE
A0
L
A1
L
A6
L
A9
DQ0-DQ7
ID read MFR code
ID read device code
Read
H
V
Code
ID
L
L
H
H
A0
X
X
A0
L
L
L
V
Code
ID
L
L
H
A1
X
A6
X
X
A6
L
A9
X
DOUT
High Z
High Z
Standby
H
L
X
H
H
X
Output disable
Write
H
X
X
L
L
A1
H
A9
D
IN
Enable sector protect
Sector unprotect
Verify sector protect
L
V
Pulse/ L
Pulse/ L
H
V
X
ID
ID
L
V
L
H
H
L
V
X
ID
ID
L
L
L
H
V
Code
ID
L = Low (<V ); H = High (>V ); V = 12.0 ± 0.5V; X = don’t car .
IL
IH
ID
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Item
Description
Selected by A9 = V (11.5–12.5V), CE = OE = A1 = A6 = L, enabling outputs.
ID
ID MFR code,
device code
When A0 is low (V ) the output data = 52h, a unique Mfr. code for Alliance Semiconductor Flash products.
IL
When A0 is high (V ), DOUT represents the device code for the AS29F040.
IH
Selected with CE = OE = L, WE = H. Data is valid in tACC time after addresses are stable, tCE after CE is low
and tOE after OE is low.
Read mode
Standby
Selected with CE = H. Part is powered down, and ICC reduced to <1.0 mA for TTL input levels and <100 µA
for CMOS levels. If activated during an automated on-chip algorithm, the device completes the operation
before entering standby.
Output disable Part remains powered up; but outputs disabled with OE pulled high.
Selected with CE = WE = L, OE = H. Accomplish all Flash erasure and programming through the command
register. Contents of command register serve as inputs to the internal state machine. Address latching occurs
on the falling edge of WE or CE, whichever occurs late . Data latching occurs on the rising edge WE or CE,
Write
whichever occurs first. Filters on WE prevent spurious noise events from appearing as write commands.
Enable
Hardware protection circuitry implemented with external programming equipment causes the device to
sector protect disable program and erase operations for specified sectors.
Sector
unprotect
Disables sector protection for all sectors using external programming equipment. All sectors must be
protected prior to sector unprotection.
Verifies write protection for sector. Sectors are protected from program/ erase operations on commercial
programming equipment. Determine if sector protection exists in a system by writing the ID read command
Verify
sector protect sequence and reading location XXX02h, where address bits A16–18 select the defined sector addresses.
A logical 1 on DQ0 indicates a protected sector; a logical 0 indicates an unprotected sector.
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ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
