VHH on the WP#/ACC pin, the device automatically en-
ters the Unlock Bypass mode. The system may then
write the two-cycle Unlock Bypass program command
sequence. The device uses the higher voltage on the
WP#/ACC pin to accelerate the operation. Note that
the WP#/ACC pin must not be at VHH any operation
other than accelerated programming, or device dam-
age may result. In addition, the WP#/ACC pin must not
be left floating or unconnected; inconsistent behavior
of the device may result.
algorithm. The device does not require the system to
preprogram prior to erase. The Embedded Erase algo-
rithm automatically preprograms and verifies the entire
memory for an all zero data pattern prior to electrical
erase. The system is not required to provide any con-
trols or timings during these operations. Table 13
shows the address and data requirements for the chip
erase command sequence.
When the Embedded Erase algorithm is complete,
that bank returns to the read mode and addresses are
no longer latched. The system can determine the sta-
tus of the erase operation by using DQ7, DQ6, DQ2,
or RY/BY#. Refer to the Write Operation Status sec-
tion for information on these status bits.
Figure 4 illustrates the algorithm for the program oper-
ation. Refer to the Erase and Program Operations
table in the AC Characteristics section for parameters,
and Figure 18 for timing diagrams.
Any commands written during the chip erase operation
are ignored. However, note that a hardware reset im-
mediately terminates the erase operation. If that oc-
curs, the chip erase command sequence should be
reinitiated once that bank has returned to reading
array data, to ensure data integrity.
START
Figure 5 illustrates the algorithm for the erase opera-
tion. Refer to the Erase and Program Operations ta-
bles in the AC Characteristics section for parameters,
and Figure 20 section for timing diagrams.
Write Program
Command Sequence
Data Poll
from System
Sector Erase Command Sequence
Embedded
Program
algorithm
Sector erase is a six bus cycle operation. The sector
erase command sequence is initiated by writing two
unlock cycles, followed by a set-up command. Two ad-
ditional unlock cycles are written, and are then fol-
lowed by the address of the sector to be erased, and
the sector erase command. Table 13 shows the ad-
dress and data requirements for the sector erase com-
mand sequence.
in progress
Verify Data?
No
Yes
No
The device does not require the system to preprogram
prior to erase. The Embedded Erase algorithm auto-
matically programs and verifies the entire memory for
an all zero data pattern prior to electrical erase. The
system is not required to provide any controls or tim-
ings during these operations.
Increment Address
Last Address?
Yes
Programming
Completed
After the command sequence is written, a sector erase
time-out of 50 µs occurs. During the time-out period,
additional sector addresses and sector erase com-
mands (for sectors within the same bank) may be writ-
ten. Loading the sector erase buffer may be done in
any sequence, and the number of sectors may be from
one sector to all sectors. The time between these ad-
ditional cycles must be less than 50 µs, otherwise era-
sure may begin. Any sector erase address and
command following the exceeded time-out may or may
not be accepted. It is recommended that processor in-
terrupts be disabled during this time to ensure all com-
mands are accepted. The interrupts can be re-enabled
after the last Sector Erase command is written. Any
command other than Sector Erase or Erase Sus-
Note: See Table 13 for program command sequence.
Figure 4. Program Operation
Chip Erase Command Sequence
Chip erase is a six bus cycle operation. The chip erase
command sequence is initiated by writing two unlock
cycles, followed by a set-up command. Two additional
unlock write cycles are then followed by the chip erase
command, which in turn invokes the Embedded Erase
26
Am29DL320G
September 27, 2004
SPANSION [ SPANSION ]
