A d v a n c e
I n f o r m a t i o n
Command Definitions
Writing specific address and data commands or sequences into the command
register initiates device operations.
and
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 com-
mand 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.
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 ex-
ception. See the Erase Suspend/Erase Resume Commands section 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 sec-
tion for more information. The Read-Only Operations–“AC
provides the read parameters, and
shows the timing
diagram.
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 ig-
nores 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.
January 28, 2005 S29GLxxxA_00_A2
S29GLxxxA MirrorBit™ Flash Family
43
SPANSION [ SPANSION ]
