EN29F080 Datasheet, PDF (10/37 Pages) List of Unclassifed Manufacturers – 8 Megabit (1024K x 8-bit) Flash Memory

EN29F080
The reset command may be written between the sequence cycles in an autoselect command sequence.
Once in the autoselect mode, the reset command must be written to return to reading array data.
If DQ5 goes high during a program or erase operation, writing the reset command returns the device to
reading array data (also applies during Erase Suspend).
Autoselect Command Sequence
The autoselect command sequence allows the host system to access the manufacturer and devices
codes, and determine whether or not a sector is protected. The Command Definitions table shows the
address and data requirements. This is an alternative method which is intended for PROM programmers
and requires V_ID on address bit A9.
Two unlock cycles followed by the autoselect command initiate the autoselect command sequence.
Autoselect mode is then entered and the system may read at any address any number of times, without
needing another command sequence.
The system must write the reset command to exit the autoselect mode and return to reading array data.
Byte Programming Command
Programming the EN29F080 is performed on a byte-by-byte basis using a four bus-cycle operation
(two unlock write cycles followed by the Program Setup command and Program Data Write cycle).
When the program command is executed, no additional CPU controls or timings are necessary. An
internal timer terminates the program operation automatically. Address is latched on the falling edge
of CE or W E , whichever is last; data is latched on the rising edge of CE or W E , whichever is first.
The program operation is completed when EN29F080 returns the equivalent data to the programmed
location.
Programming status may be checked by sampling data on DQ7 (DATA polling) or on DQ6 (toggle
bit). Changing data from 0 to 1 requires an erase operation. When programming time limit is
exceeded, DQ5 will produce a logical “1” and a Reset command can return the device to Read mode.
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 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.
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Rev. C, Issue Date: 2001/07/05
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