
30
S71AL016M
S71AL016M_M0 A0 February 23, 2005
A d v a n c e I n f o r m a t i o n
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 on page 33
for more
information 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
Command”
section, next.
See also
Requirements for Reading Array Data on page 17
for more informa-
tion. The
Table 14 on page 47
provides the read parameters, and
Figure 13, on
page 47
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.
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 reading array data (also applies to autoselect during
Erase Suspend).
If DQ5 goes high during a program or erase operation, writing the reset com-
mand returns the device to reading array data (also applies during Erase
Suspend).
Autoselect Command Sequence
The autoselect command sequence allows the host system to access the manu-
facturer and devices codes, and determine whether or not a sector is protected.
Table 10 on page 37
and
Table 11 on page 43
show the address and data re-
quirements. This method is an alternative to that shown in
Table 4 on page 22
,
which is intended for PROM programmers and requires V
ID
on address bit A9.
The autoselect command sequence is initiated by writing two unlock cycles, fol-
lowed by the autoselect command. The device then enters the autoselect mode,
and the system may read at any address any number of times, without initiating
another command sequence.
A read cycle at address XX00h retrieves the manufacturer code. A read cycle at
address XX01h returns the device code. A read cycle containing a sector address
(SA) and the address XX02h in word mode returns XX01h if that sector is pro-
tected, or 00h if it is unprotected. Refer to
Table 2 on page 20
and
Table 3 on
page 21
for valid sector addresses.
The system must write the reset command to exit the autoselect mode and re-
turn to reading array data.