EN29LV400A
Unlock Bypass
To speed up programming operation, the Unlock Bypass Command may be used. Once this feature
is activated, the shorter two cycle Unlock Bypass Program command can be used instead of the
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.
This Data Sheet may be revised by subsequent versions
or modifications due to changes in technical specifications.
©2005 Eon Silicon Solution, Inc., www.essi.com.tw
13
Rev. A, Issue Date: 2005/01/07
EON [ EON SILICON SOLUTION INC. ]
