COMMAND DEFINITIONS
Writing specific address and data commands or se-
quences into the command register initiates device op-
erations. Table 12 defines the valid register command
sequences. 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 return the device to reading array
data.
The reset command may be written between the
sequence cycles in a program command sequence
before programming begins. This resets the bank to
which the system was writing to the read mode. If the
program command sequence is written to a bank that
is in the Erase Suspend mode, writing the reset
command returns that bank to the erase-sus-
pend-read mode. Once programming begins, however,
the device ignores reset commands until the operation
is complete.
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 AC Characteristics section for timing
diagrams.
The reset command may be written between the se-
quence cycles in an autoselect command sequence.
Once in the autoselect mode, the reset command
must be written to return to the read mode. If a bank
entered the autoselect mode while in the Erase Sus-
pend mode, writing the reset command returns that
bank to the erase-suspend-read mode.
Reading Array Data
The device is automatically set to reading array data
after device power-up. No commands are required to
retrieve data. Each bank is ready to read array data
after completing an Embedded Program or Embedded
Erase algorithm.
If DQ5 goes high during a program or erase operation,
writing the reset command returns the banks to the
read mode (or erase-suspend-read mode if that bank
was in Erase Suspend).
After the device accepts an Erase Suspend command,
the corresponding bank enters the erase-sus-
pend-read mode, after which the system can read
data from any non-erase-suspended sector within the
same bank. The system can read array data using the
standard read timing, except that if it reads at an ad-
dress within erase-suspended sectors, the device out-
puts status data. After completing a programming
operation in the Erase Suspend mode, the system
may once again read array data with the same excep-
tion. See the Erase Suspend/Erase Resume Com-
mands section for more information.
Autoselect Command Sequence
The autoselect command sequence allows the host
system to access the manufacturer and device codes,
and determine whether or not a sector is protected.
The autoselect command sequence may be written to
an address within a bank that is either in the read or
erase-suspend-read mode. The autoselect command
may not be written while the device is actively pro-
gramming or erasing in another bank.
The autoselect command sequence is initiated by first
writing two unlock cycles. This is followed by a third
write cycle that contains the bank address and the au-
toselect command. The bank then enters the autose-
lect mode. The system may read any number of
autoselect codes without re initiating the command se-
quence.
The system must issue the reset command to return a
bank to the read (or erase-suspend-read) mode if DQ5
goes high during an active program or erase opera-
tion, or if the bank is in the autoselect mode. See the
next section, Reset Command, for more information.
See also Requirements for Reading Array Data in the
Device Bus Operations section for more information.
The Read-Only Operations table provides the read pa-
rameters, and Figure 14 shows the timing diagram.
Table 12 shows the address and data requirements.
To determine sector protection information, the system
must write to the appropriate bank address (BA) and
sector address (SA). Table 2 shows the address range
and bank number associated with each sector.
Reset Command
Writing the reset command resets the banks to the
read or erase-suspend-read mode. Address bits are
don’t cares for this command.
The system must write the reset command to return to
the read mode (or erase-suspend-read mode if the
bank was previously in Erase Suspend).
The reset command may be written between the se-
quence cycles in an erase command sequence before
erasing begins. This resets the bank to which the sys-
tem was writing to the read mode. Once erasure be-
gins, however, the device ignores reset commands
until the operation is complete.
Enter Secured Silicon Sector/Exit Secured
Silicon Sector
Command Sequence
The Secured Silicon Sector region provides a secured
data area containing a random, sixteen-byte electronic
serial number (ESN). The system can access the Se-
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