M29W320ET, M29W320EB
Fast Program Commands
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The third bus cycle latches the Address and
the Data of the second word to be written and
starts the Program/Erase Controller.
There are two Fast Program commands available
to improve the programming throughput, by writing
several adjacent words or bytes in parallel. The
Quadruple Byte Program command is available for
x8 operations, while the Double Word Program
command is available for x16 operations.
Fast Program commands should not be attempted
when VPP/WP is not at VPP. Care must be taken
because applying a 12V VPP voltage to the VPP/
WP pin will temporarily unprotect any protected
block.
Unlock Bypass Command
The Unlock Bypass command is used in conjunc-
tion with the Unlock Bypass Program command to
program the memory faster than with the standard
program commands. When the cycle time to the
device is long, considerable time saving can be
made by using these commands. Three Bus Write
operations are required to issue the Unlock By-
pass command.
After programming has started, Bus Read opera-
tions output the Status Register content.
Once the Unlock Bypass command has been is-
sued the memory enters Unlock Bypass mode.
The Unlock Bypass Program command can then
be issued to program addresses or the Unlock By-
pass Reset command can be issued to return to
Read mode. In Unlock Bypass mode the memory
can be read as if in Read mode.
When VPP is applied to the VPP/Write Protect pin
the memory automatically enters the Unlock By-
pass mode and the Unlock Bypass Program com-
mand can be issued immediately. Care must be
taken because applying a 12V VPP voltage to the
VPP/WP pin will temporarily unprotect any protect-
ed block.
After the program operation has completed the
memory will return to the Read mode, unless an
error has occurred. When an error occurs Bus
Read operations will continue to output the Status
Register. A Read/Reset command must be issued
to reset the error condition and return to Read
mode.
Note that the Fast Program commands cannot
change a bit set at ’0’ back to ’1’. One of the Erase
Commands must be used to set all the bits in a
block or in the whole memory from ’0’ to ’1’.
Typical Program times are given in Table
6., Program, Erase Times and Program, Erase
Endurance Cycles
Quadruple Byte Program Command. The Qua-
druple Byte Program command is used to write a
page of four adjacent Bytes in parallel. The four
bytes must differ only for addresses A0, DQ15A-1.
Five bus write cycles are necessary to issue the
Quadruple Byte Program command.
Unlock Bypass Program Command
The Unlock Bypass Program command can be
used to program one address in the memory array
at a time. The command requires two Bus Write
operations, the final write operation latches the ad-
dress and data, and starts the Program/Erase
Controller.
The Program operation using the Unlock Bypass
Program command behaves identically to the Pro-
gram operation using the Program command. The
operation cannot be aborted, a Bus Read opera-
tion outputs the Status Register. See the Program
command for details on the behavior.
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The first bus cycle sets up the Quadruple Byte
Program Command.
The second bus cycle latches the Address and
the Data of the first byte to be written.
The third bus cycle latches the Address and
the Data of the second byte to be written.
The fourth bus cycle latches the Address and
the Data of the third byte to be written.
Unlock Bypass Reset Command
The Unlock Bypass Reset command can be used
to return to Read/Reset mode from Unlock Bypass
Mode. Two Bus Write operations are required to
issue the Unlock Bypass Reset command. Read/
Reset command does not exit from Unlock Bypass
Mode.
The fifth bus cycle latches the Address and the
Data of the fourth byte to be written and starts
the Program/Erase Controller.
Double Word Program Command. The Double
Word Program command is used to write a page
of two adjacent words in parallel. The two words
must differ only for the address A0.
Three bus write cycles are necessary to issue the
Double Word Program command.
Chip Erase Command
The Chip Erase command can be used to erase
the entire chip. Six Bus Write operations are re-
quired to issue the Chip Erase Command and start
the Program/Erase Controller.
If any blocks are protected then these are ignored
and all the other blocks are erased. If all of the
blocks are protected the Chip Erase operation ap-
pears to start but will terminate within about 100µs,
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The first bus cycle sets up the Double Word
Program Command.
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The second bus cycle latches the Address and
the Data of the first word to be written.
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STMICROELECTRONICS [ ST ]
