MX29LV400T/B
The device provides Q2, Q3, Q5, Q6, Q7, and RY/BY to
determine the status of a write operation. If the program
operation was unsuccessful, the data on Q5 is "1"(see
Table 7), indicating the program operation exceed inter-
nal timing limit.The automatic programming operation is
completed when the data read on Q6 stops toggling for
two consecutive read cycles and the data on Q7 and Q6
are equivalent to data written to these two bits, at which
time the device returns to the Read mode(no program
verify command is required).
ERASE SUSPEND
This command only has meaning while the state ma-
chine is executing Automatic Sector Erase operation,
and therefore will only be responded during Automatic
Sector Erase operation. When the Erase Suspend com-
mand is written during a sector erase operation, the de-
vice requires a maximum of 20us to suspend the erase
operations.However,When the Erase Suspend command
is written during the sector erase time-out, the device
immediately terminates the time-out period and suspends
the erase operation. After this command has been ex-
ecuted, the command register will initiate erase suspend
mode. The state machine will return to read mode auto-
matically after suspend is ready. At this time, state ma-
chine only allows the command register to respond to
the Read Memory Array, Erase Resume and program
commands.
WORD/BYTE PROGRAM COMMAND SEQUENCE
The device programs one byte of data for each program
operation. The command sequence requires four bus
cycles, and is initiated by writing two unlock write cycles,
followed by the program set-up command. The program
address and data are written next, which in turn initiate
the Embedded Program algorithm. The system is not
required to provide further controls or timings.The device
automatically generates the program pulses and verifies
the programmed cell margin. Table 1 shows the address
and data requirements for the byte program command
sequence.
The system can determine the status of the program
operation using the Q7 or Q6 status bits, just as in the
standard program operation. After an erase-suspend pro-
gram operation is complete, the system can once again
read array data within non-suspended sectors.
When the Embedded Program algorithm is complete,
the device then returns to reading array data and
addresses are no longer latched. The system can
determine the status of the program operation by using
Q7, Q6, or RY/BY. See "Write Operation Status" for
information on these status bits.
ERASE RESUME
This command will cause the command register to clear
the suspend state and return back to Sector Erase mode
but only if an Erase Suspend command was previously
issued. Erase Resume will not have any effect in all
other conditions. Another Erase Suspend command can
be written after the chip has resumed erasing.
Any commands written to the device during the Em-
bedded Program Algorithm are ignored. Note that a
hardware reset immediately terminates the programming
operat ion.The Byte Program command sequence should
be reinitiated once the device has reset to reading array
data, to ensure data integrity.
AUTOMATIC PROGRAM COMMANDS
To initiate Automatic Program mode, A three-cycle com-
mand sequence is required. There are two "unlock" write
cycles. These are followed by writing the Automatic Pro-
gram command A0H.
Programming is allowed in any sequence and across
sector boundaries. A bit cannot be programmed from a
"0" back to a "1". Attempting to do so may halt the
operation and set Q5 to "1" ,” or cause the Data Polling
algorithm to indicate the operation was successful.
However, a succeeding read will show that the data is
still "0". Only erase operations can convert a "0" to a
"1".
Once the Automatic Program command is initiated, the
next WE pulse causes a transition to an active program-
ming operation. Addresses are latched on the falling
edge, and data are internally latched on the rising edge
of the WE or CE, whichever happens first. The rising
edge of WE or CE, whichever happens first, also begins
the programming operation. The system is not required
to provide further controls or timings. The device will
automatically provide an adequate internally generated
program pulse and verify margin.
WRITE OPERSTION STATUS
The device provides several bits to determine the sta-
tus of a write operation: Q2, Q3, Q5, Q6, Q7, and RY/
BY.Table 10 and the following subsections describe the
P/N:PM0710
REV. 1.4, NOV. 23, 2001
13
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