MX29LV64xM H/L
ware reset immediately terminates the programming op-
eration. The Byte/Word Program command sequence
should be reinitiated once the device has reset to read-
ing array data, to ensure data integrity.
multiple times, the address/data pair counter will be
decremented for every data load operation.The host sys-
tem must therefore account for loading a write-buffer lo-
cation more than once.The counter decrements for each
data load operation, not for each unique write-buffer-ad-
dress location. Note also that if an address location is
loaded more than once into the buffer, the final data loaded
for that address will be programmed.
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 op-
eration and set Q5 to "1", or cause the Data# Polling
algorithm to indicate the operation was successful. How-
ever, a succeeding read will show that the data is still
"0". Only erase operations can convert a "0" to a "1".
Once the specified number of write buffer locations have
been loaded, the system must then write the Program
Buffer to Flash command at the sector address. Any
other address and data combination aborts the Write
Buffer Programming operation. The device then begins
programming. Data polling should be used while monitor-
ing the last address location loaded into the write buffer.
Q7, Q6, Q5, and Q1 should be monitored to determine
the device status during Write Buffer Programming.
Write Buffer Programming
Write Buffer Programming allows the system write to a
maximum of 16 words/32 bytes in one programming op-
eration.This results in faster effective programming time
than the standard programming algorithms. The Write
Buffer Programming command sequence is initiated by
first writing two unlock cycles.This is followed by a third
write cycle containing the Write Buffer Load command
written at the Sector Address in which programming will
occur. The fourth cycle writes the sector address and
the number of word locations, minus one, to be pro-
grammed. For example, if the system will program 6
unique address locations, then 05h should be written to
the device. This tells the device how many write buffer
addresses will be loaded with data and therefore when to
expect the Program Buffer to Flash command.The num-
ber of locations to program cannot exceed the size of
the write buffer or the operation will abort.
The write-buffer programming operation can be suspended
using the standard program suspend/resume commands.
Upon successful completion of the Write Buffer Program-
ming operation, the device is ready to execute the next
command.
TheWrite Buffer Programming Sequence can be aborted
in the following ways:
•
•
•
Load a value that is greater than the page buffer size
during the Number of Locations to Program step.
Write to an address in a sector different than the one
specified during the Write-Buffer-Load command.
Write an Address/Data pair to a different write-buffer-
page than the one selected by the Starting Address
during the write buffer data loading stage of the op-
eration.
The fifth cycle writes the first address location and data
to be programmed.The write-buffer-page is selected by
address bits AMAX-4. All subsequent address/data pairs
must fall within the selected-write-buffer-page.The sys-
tem then writes the remaining address/data pairs into
the write buffer. Write buffer locations may be loaded in
any order.
•
Write data other than the Confirm Command after the
specified number of data load cycles.
The abort condition is indicated by Q1 = 1, Q7 = DATA#
(for the last address location loaded), Q6 = toggle, and
Q5=0.AWrite-to-Buffer-Abort Reset command sequence
must be written to reset the device for the next opera-
tion. Note that the full 3-cycle Write-to-Buffer-Abort Re-
set command sequence is required when using Write-
Buffer-Programming features in Unlock Bypass mode.
The write-buffer-page address must be the same for all
address/data pairs loaded into the write buffer. (This
means Write Buffer Programming cannot be performed
across multiple write-buffer pages.This also means that
Write Buffer Programming cannot be performed across
multiple sectors. If the system attempts to load program-
ming data outside of the selected write-buffer page, the
operation will abort.
Program Suspend/Program Resume Command
Sequence
The Program Suspend command allows the system to
interrupt a programming operation or a Write to Buffer
Note that if a Write Buffer address location is loaded
P/N:PM1093
REV. 1.1, AUG. 11, 2005
21
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