EN29LV400
normal four cycle Program Command to program the device. This mode is exited after issuing the
Unlock Bypass Reset Command. The device powers up with this feature disabled.
Chip Erase Command
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 algorithm. The device does not require
the system to preprogram prior to erase. The Embedded Erase algorithm 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 controls or timings during these operations. The Command Definitions table shows the
address and data requirements for the chip erase command sequence.
Any commands written to the chip during the Embedded Chip Erase algorithm are ignored.
The system can determine the status of the erase operation by using DQ7, DQ6, or DQ2. See “Write
Operation Status” for information on these status bits. When the Embedded Erase algorithm is complete,
the device returns to reading array data and addresses are no longer latched.
Flowchart 4 illustrates the algorithm for the erase operation. See the Erase/Program Operations tables in
“AC Characteristics” for parameters, and to the Chip/Sector Erase Operation Timings for timing
waveforms.
Sector Erase Command Sequence
Sector erase is a six bus cycle operation. The sector erase command sequence is initiated by writing two
un-lock cycles, followed by a set-up command. Two additional unlock write cycles are then followed by the
address of the sector to be erased, and the sector erase command. The Command Definitions table
shows the address and data requirements for the sector erase command sequence.
Once the sector erase operation has begun, only the Erase Suspend command is valid. All other
commands are ignored.
When the Embedded Erase algorithm is complete, the device returns to reading array data and addresses
are no longer latched. The system can determine the status of the erase operation by using DQ7, DQ6, or
DQ2. Refer to “Write Operation Status” for information on these status bits. Flowchart 4 illustrates the
algorithm for the erase operation. Refer to the Erase/Program Operations tables in the “AC
Characteristics” section for parameters, and to the Sector Erase Operations Timing diagram for timing
waveforms.
Erase Suspend / Resume Command
The Erase Suspend command allows the system to interrupt a sector erase operation and then read data
from, or program data to, any sector not selected for erasure. This command is valid only during the
sector erase operation. The Erase Suspend command is ignored if written during the chip erase operation
or Embedded Program algorithm. Addresses are don’t-cares when writing the Erase Suspend command.
When the Erase Suspend command is written during a sector erase operation, the device requires a
maximum of 20 µs to suspend the erase operation.
After the erase operation has been suspended, the system can read array data from or program data to
any sector not selected for erasure. (The device “erase suspends” all sectors selected for erasure.)
Normal read and write timings and command definitions apply. Reading at any address within erase-
suspended sectors produces status data on DQ7–DQ0. The system can use DQ7, or DQ6 and DQ2
together, to determine if a sector is actively erasing or is erase-suspended. See “Write Operation Status”
for information on these status bits.
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc., www.essi.com.tw
Rev. C, Issue Date: 2004/03/18
13
ESMT [ ELITE SEMICONDUCTOR MEMORY TECHNOLOGY INC. ]
