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. Table 30 on page 54 and Table 31 on
page 55 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.
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 Erase Suspend/Erase Resume Commands on page 52 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 Characteristics on
page 66 provide the read parameters, and Figure 13, on page 67 shows the tim-
ing 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 autose-
lect 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.
April 22, 2005 S29GL-A_00_A3
S29GL-A MirrorBit™ Flash Family
43
SPANSION [ SPANSION ]
