D a t a S h e e t
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 Com-
mand, next.
See also Requirements for Reading Array Data, on page 11 for more information.
The table provides the read parameters, and Figure 13, on page 38 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 autoselect
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 command
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 5, on page 25 shows the address and data requirements. This method is an
alternative to that shown in Table 4, on page 16, which is intended for PROM pro-
grammers and requires V on address bit A9.
ID
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 in word mode (or 02h in byte mode) returns the device code. A
read cycle containing a sector address (SA) and the address 02h in word mode
(or 04h in byte mode) returns 01h if that sector is protected, or 00h if it is un-
protected. Refer to Table 2, on page 14 and Table 3, on page 15 for valid sector
addresses.
The system must write the reset command to exit the autoselect mode and return
to reading array data.
Word/Byte Program Command Sequence
The system may program the device by word or byte, depending on the state of
the BYTE# pin. Programming is a four-bus-cycle operation. The program com-
mand sequence is initiated by writing two unlock write cycles, followed by the
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