AM29LV6402M Datasheet, PDF (26/57 Pages) SPANSION – 128 Megabit (4 M x 32-Bit/8 M x 16-Bit) MirrorBit 3.0 Volt-only Uniform Sector Flash Memory with Versatile I/O Control

COMMAND DEFINITIONS
Writing specific address and data commands or se-
quences into the command register initiates device op-
erations. Tables 10 and 11 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 read-
ing 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 pro-
gramming operation in the Erase Suspend mode, the
system may once again read array data with the same
exception. 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 or DQ13 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 section for more information.
The Read-Only Operations table provides the read pa-
rameters, and Figure 14 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 se-
quence cycles in an erase command sequence before
erasing begins. This resets the device to the read
mode. Once erasure begins, however, the device ig-
nores 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 be-
gins, however, the device ignores reset commands
until the operation is complete.
The reset command may be written between the se-
quence 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 de-
vice entered the autoselect mode while in the Erase
Suspend mode, writing the reset command returns the
device to the erase-suspend-read mode.
If DQ5 or DQ13 goes high during a program or erase
operation, writing the reset command returns the de-
vice to the read mode (or erase-suspend-read mode if
the device was in Erase Suspend).
Note that if DQ1 or DQ9 goes high during a Write
Buffer Programming operation, the system must write
the Write-to-Buffer-Abort Reset command sequence
to reset the device for the next operation.
Autoselect Command Sequence
The autoselect command sequence allows the host
system to access the manufacturer and device codes,
and determine whether or not a sector is protected.
Table 11 shows the address and data requirements.
This method is an alternative to that shown in Table 3,
which is intended for PROM programmers and re-
quires V_ID on address pin A9. The autoselect com-
mand sequence may be written to an address that is
either in the read or erase-suspend-read mode. The
autoselect command may not be written while the de-
vice is actively programming or erasing.
The autoselect command sequence is initiated by first
writing two unlock cycles. This is followed 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
initiating another autoselect command sequence:
■ A read cycle at address XX00h returns the manu-
facturer code.
■ Three read cycles at addresses 01h, 0Eh, and 0Fh
return the device code.
■ A read cycle to an address containing a sector ad-
dress (SA), and the address 02h on A7–A0 in dou-
bleword mode returns 0101h if the sector is
protected, or 0000h if it is unprotected.
The system must write the reset command to return to
the read mode (or erase-suspend-read mode if the de-
vice was previously in Erase Suspend).
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Am29LV6402M
January 23, 2006