am49lv128bm Meet Spansion Inc., am49lv128bm Datasheet - Page 27

• Manufacturer Part Number: am49lv128bm
• Description: Stacked Multi-chip Package Mcp ,128 Megabit 8 M ? 16-bit ,uniform Sector Flash Memory And 32 Mbit 2 M ? 16-bit Pseudo-static Ram With Page Mode Featuring Mirrorbit Technology,supplemental Datasheet
• Manufacturer: Meet Spansion Inc.

suspended sector. After completing a programming
operation in the Erase Suspend mode, the system
may once again read array data with the same excep-
tion. See the Erase Suspend/Erase Resume Com-
mands 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 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 infor-
mation.
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 goes high during a program or erase operation,
writing the reset command returns the device to the
read mode (or erase-suspend-read mode if the device
was in Erase Suspend).
Note that if DQ1 goes high during a Write Buffer Pro-
gramming 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,
June 17, 2004
Am49LV128BM
and determine whether or not a sector is protected.
Tables 9 show the address and data requirements.
The autoselect command sequence may be written to
an address that is either in the read or erase-suspend-
read mode. The autoselect command may not be writ-
ten while the device is actively programming or eras-
ing.
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:
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).
Enter SecSi Sector/Exit SecSi Sector
Command Sequence
The SecSi Sector region provides a secured data area
containing an 8-word random Electronic Serial Num-
ber (ESN). The system can access the SecSi Sector
region by issuing the three-cycle Enter SecSi Sector
command sequence. The device continues to access
the SecSi Sector region until the system issues the
four-cycle Exit SecSi Sector command sequence. The
Exit SecSi Sector command sequence returns the de-
vice to normal operation. Tables 9 show the address
and data requirements for both command sequences.
See also “SecSi (Secured Silicon) Sector Flash
Memory Region” for further information. Note that the
ACC function and unlock bypass modes are not avail-
able when the SecSi Sector is enabled.
Word Program Command Sequence
Programming is a four-bus-cycle operation. The pro-
gram command sequence is initiated by writing two
unlock write cycles, followed by the program set-up
command. The program address and data are written
next, which in turn initiate the Embedded Program al-
gorithm. The system is not required to provide further
controls or timings. The device automatically provides
internally generated program pulses and verifies the
programmed cell margin. Tables 9 show the address
and data requirements for the word program com-
mand 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 word
mode returns 01h if the sector is protected, or 00h if
it is unprotected.
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