FLASH
AS29F040
power-down. The command register and all internal program/ Embedded Program or Embedded Erase algorithm.
erase circuits are disabled, and the device resets. Subsequent
After the device accepts an Erase Suspend command, the
device enters the Erase Suspend mode. The system can read
array data using the standard read timings, except that if it reads
at an address within erase-suspended sectors, the device outputs
writes are ignored until VCC is greater than VLKO. The system
must provide the proper signals to the control pins to prevent
unintentional writes when VCC is greater than VLKO
.
status data. After completing a programming
operation
in the Erase Suspend mode, the system may once again read
Write Pulse “Glitch” Protection
Noise pulses of less than 5ns (typical) on OE\, CE\, or WE\
do not initiate a write cycle.
array data with the same exception. See “Erase
Erase Resume” for more information.
Suspend/
The system must issue the reset command to re-enable the
device for reading array data if DQ5 goes high, or while in the
autoselect mode. See the “Reset Command” section, next.
See also “Requirements for Reading Array Data” in the
“Device Bus Operations” section for more information. The
Read Operations table provides the read parameters, and the
Read Operation Timings diagram shows the timing diagram.
Logical Inhibit
Write cycles are inhibited by holding any one of OE\ =
VIL, CE\ = VIH or WE\ = VIH. To initiate a write cycle, CE\
and WE\ must be a logical zero while OE\ is a logical one.
Power-Up Write Inhibit
If WE\ = CE\ = VIL and OE\ = VIH during power up, the
device does not accept commands on the rising edge of WE\.
The internal state machine is automatically reset to reading
array data on power-up.
Reset Command
Writing the reset command to the device resets the device to
reading array data. Address bits are don’t care for this com-
mand.
The reset command may be written between the sequence
cycles in an erase command sequence before erasing begins.
This resets the device to reading array data. Once erasure
begins, however, the device ignores reset commands until the
operation is complete.
The reset command may be written between the sequence
cycles in a program command sequence before programming
begins. This resets the device to reading array data (also ap-
plies to programming in Erase Suspend Mode). Once program-
ming begins, however, the device ignores reset commands until
the operation is complete.
COMMAND DEFINITIONS
Writing specific address and data commands or sequences
into the command register initiates device operations. The
Command Definitions table defines the valid register com-
mand sequences. Writing incorrect address and data values
or
writing them in the improper sequence resets the device
to reading array data.
All addresses are latched on the falling edge of WE\ or CE\,
whichever happens later. All data is latched on the rising edge of
WE\ or CE\, whichever happens first. Refer to the appropriate
The reset command may be written between the sequence
cycles in an autoselect command sequence. Once in the au-
toselect mode, the reset command must be written to return
timing diagrams in the “AC Characteristics”
section.
Reading Array Data
The device is automatically set to reading array data after to reading array data (also applies to autoselect during Erase
device power-up. No commands are required to retrieve data. Suspend).
The device is also ready to read array data after completing an
If DQ5 goes high during a program or erase operation,
TABLE 3: Autoselect Codes (High Voltage Method)
Identifier Code
On DQ7 to DQ0
Description
A18 - A16 A15 - A10 A9
A8 - A7
A6
A5 - A2
A1
A0
Manufacturer ID
Device ID
X
X
X
X
V
V
X
X
V
V
X
X
V
V
V
01h
ID
IL
IL
IL
V
A4h
ID
IL
IL
IH
01h (protected)
Sector Protection
Verification
Sector
Address
X
V
X
V
X
V
V
IL
ID
IL
IH
00h
(unprotected)
AS29F040
Micross Components reserves the right to change products or specifications without notice.
Rev. 2.3 01/10
6
MICROSS [ MICROSS COMPONENTS ]
