14
P/N:PM1155
MX29LV400C T/B
REV. 1.5, APR. 24, 2006
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
Secto r Erase o peratio n. When the Erase Suspend co m-
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 co mmand
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
mo de. 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 Memor y Array, Erase Resume and program
commands.
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.
ERASE RESUME
This command will cause the co mmand 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. The mini-
mum time from Erase Resume to next Erase Suspend
is 400us. Repeatedly suspending the device mo re often
may have undetermined effects.
AUTOMA TIC PROGRAM COMMANDS
To initiate Automatic Pro gram mode, A three-cycle co m-
mand sequence is required. There are two "unlock" write
cycles. These are fo llowed by writing the Auto matic Pro-
gram command A0H.
Once the Automatic Program command is initiated, the
next WE# pulse causes a transition to an active pro-
gramming o peratio n. Addresses are latched on the fall-
ing edge, and data are internally latched o n the rising
edge o f the WE# or CE#, whiche ver 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 auto matically pro vide an adequate internally
generated pro gram pulse and verify margin.
The de vice provides Q2, Q3, Q5, Q6, Q7, and RY/BY#
to determine the status of a wr ite operation. If the pro-
gram operation was unsuccessful, the data on Q5 is
"1"(see Table 7), indicating the program o peration exceed
internal timing limit. The auto matic pro gramming o pera-
tion is completed when the data read on Q6 stops tog-
gling fo r two consecutive read cycles and the data o n Q7
and Q6 are equivalent to data written to these two bits,
at which time the de vice returns to the Read mode (no
pro gram verify co mmand is required).
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.
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.
Any commands written to the device during the Em-
bedded Program Algorithm are ignored. Note that a
hardware reset immediately terminates the programming
operation. The Byte Program command sequence should
be reinitiated once the device has reset to reading array
data, to ensure data integrity.
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".