D a t a S h e e t
10. Command Definitions
Writing specific address and data commands or sequences into the command register initiates device
operations. Table 10.1 on page 51 and Table 10.3 on page 53 define 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.
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.
10.1 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 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-read mode, after
which the system can read data from any non-erase-suspended sector. 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 on page 50 for more information.
The system must issue the reset command to return the device to the read (or erase-suspend-read) mode if
DQ5 goes high during an active program or erase operation, or if the device 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–AC Characteristics on page 64 provide the read parameters, and Figure 15.2
on page 65 shows the timing diagram.
10.2 Reset Command
Writing the reset command resets the device to the read or erase-suspend-read mode. Address bits are don’t
cares 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 the read mode. 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 the read mode. If the program command sequence is written
while the device is in the Erase Suspend mode, writing the reset command returns the device to the erase-
suspend-read mode. Once programming begins, however, the device ignores reset commands until the
operation is complete.
The reset command may be written between the sequence cycles in an autoselect command sequence.
Once in the autoselect mode, the reset command must be written to return to the read mode. If the device
entered the autoselect mode while in the Erase Suspend mode, writing the reset command returns the device
to the erase-suspend-read mode.
If DQ5 goes high during a program or erase operation, writing the reset command returns the device to the
read mode (or erase-suspend-read mode if the device was in Erase Suspend).
Note that if DQ1 goes high during a Write Buffer Programming operation, the system must write the Write-to-
Buffer-Abort Reset command sequence to reset the device for the next operation.
November 16, 2007 S29GL-N_01_09
S29GL-N MirrorBit® Flash Family
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SPANSION [ SPANSION ]
