Logical Inhibit
Write cycles are inhibited by holding any one of OE# = V , CE# = V or WE# =
IL
IH
V . To initiate a write cycle, CE# and WE# must be a logical zero while OE# is a
IH
logical one.
Power-Up Write Inhibit
If WE# = CE# = V and OE# = V during power up, the device does not accept
IL
IH
commands on the rising edge of WE#. The internal state machine is automatically
reset to reading array data on power-up.
Command Definitions
Writing specific address and data commands or sequences into the command
register initiates device operations. Tables 10–11 define the valid register com-
mand sequences. Note that writing incorrect address and data values or writing
them in the improper sequence may place the device in an unknown state. A
reset command is then required to set the device for the next operation.
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 timing diagrams in the “AC Characteristics” section.
Reading Array Data
The device is automatically set to reading array data after device power-up. No
commands are required to retrieve data. The device is also ready to read array
data after completing an Embedded Program or Embedded Erase algorithm.
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 status data. After completing a programming operation in
the Erase Suspend mode, the system may once again read array data with the
same exception. See “Erase Suspend/Erase Resume Commands” for more in-
formation on this mode.
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 Com-
mand” 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 pa-
rameters, and Figure 13 shows the timing diagram.
Reset Command
Writing the reset command to the device resets the device to reading array data.
Address bits are don’t care for this command.
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 read-
ing array data (also applies to programming in Erase Suspend mode). Once
programming begins, however, the device ignores reset commands until the op-
eration is complete.
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