COMMAND DEFINITIONS
Writing specific address and data commands or
sequences into the command register initiates
device operations.
Table 14, on page 29
defines
the valid register command sequences.
Note
that 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 required to return the device to
normal operation.
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 Char-
acteristics section for timing diagrams.
quence before programming begins. This resets
the device to which the system was writing to
the read mode. If the program command se-
quence is written to a sector that is in the Erase
Suspend mode, writing the reset command re-
turns the device to the erase-suspend-read
mode. Once programming begins, however, the
device ignores reset commands until the opera-
tion 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 au-
toselect 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 op-
eration, writing the reset command returns the
d e v i c e t o t h e r e a d m o d e ( o r e ra s e - s u s -
pend-read mode if the device was in Erase Sus-
pend).
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-sus-
pend-read mode, after which the system can
read data from any non-erase-suspended sec-
tor. 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 28
The system
return the device to the read (or erase-sus-
pend-read) mode if DQ5 goes high during an
active program or erase operation, or if the de-
vice is in the autoselect mode. See the next
section,
“Reset Command,
for more informa-
tion.
See also
“Requirements for Reading Array
Data” on page 11
Read-Only Operations table provides the read
parameters, and
shows
the timing diagram.
Autoselect Command Sequence
The autoselect command sequence allows the
host system to read several identifier codes at
specific addresses:
Table 13.
Identifier Code
Manufacturer ID
Device ID
SecSi Sector Factory Protect
Sector Group Protect Verify
Autoselect Codes
Address
00h
01h
03h
(SA)02h
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 se-
quence before erasing begins. This resets the
device to which the system was writing to the
read mode. Once erasure begins, however, the
device ignores reset commands until the opera-
tion is complete.
The reset command may be written between
the sequence cycles in a program command se-
November 15, 2004
Table 14, on page 29
shows the address and
data requirements. This method is an alterna-
tive to that shown in
Table 6, on page 16,
which is intended for PROM programmers and
requires V
ID
on address pin A9. The autoselect
command sequence may be written to an ad-
dress within sector that is either in the read or
erase-suspend-read mode. The autoselect
command may not be written while the device
is actively programming or erasing.
The autoselect command sequence is initiated
by first writing two unlock cycles. This is fol-
lowed by a third write cycle that contains the
autoselect command. The device then enters
the autoselect mode. The system may read at
any address any number of times without initi-
ating another autoselect command sequence.
The system must write the reset command to
r e t u r n t o t h e r e a d m o d e ( o r e ra s e - s u s -
pend-read mode if the device was previously in
Erase Suspend).
Am29LV320D
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SPANSION [ SPANSION ]
