EN29GL064 Datasheet, PDF (21/66 Pages) Eon Silicon Solution Inc. – 64 Megabit (8192K x 8-bit / 4096K x 16-bit) Flash Memory

Preliminary EN29GL064
Write Buffer Programming
Write Buffer Programming allows the system to write a maximum of 16 words in one programming
operation. This results in a faster effective word programming time than the standard “word”
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 occurs. At this point, the system writes the number
of “word locations minus 1” that are loaded into the page buffer at the Sector Address in which
programming occurs. This tells the device how many write buffer addresses are loaded with data and
therefore when to expect the “Program Buffer to Flash” confirm command. The number of locations to
program cannot exceed the size of the write buffer or the operation aborts. (Number loaded = the
number of locations to program minus 1. For example, if the system programs 6 address locations, then
05h should be written to the device.)
The system then writes the starting address/data combination. This starting address is the first
address/data pair to be programmed, and selects the “write-buffer-page” address. All subsequent
address/data pairs must fall within the elected-write-buffer-page.
The “write-buffer-page” is selected by using the addresses A21–A5.
The “write-buffer-page” addresses 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 programming data outside of the selected “write-buffer-page”, the operation
ABORTs.)
After writing the Starting Address/Data pair, the system then writes the remaining address/data pairs
into the write buffer.
Note that if a Write Buffer address location is loaded multiple times, the “address/data pair” counter is
decremented for every data load operation. Also, the last data loaded at a location before the “Program
Buffer to Flash” confirm command is the data programmed into the device. It is the software's
responsibility to comprehend ramifications of loading a write-buffer location more than once. The
counter decrements for each data load operation, NOT for each unique write-buffer-address location.
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/data write combinations
abort the Write Buffer Programming operation. The Write Operation Status bits should be used while
monitoring the last address location loaded into the write buffer. This eliminates the need to store an
address in memory because the system can load the last address location, issue the program confirm
command at the last loaded address location, and then check the write operation status at that same
address. DQ7, DQ6, DQ5, DQ2, and DQ1 should be monitored to determine the device status during
Write Buffer Programming.
The write-buffer “embedded” programming operation can be suspended using the standard
suspend/resume commands. Upon successful completion of the Write Buffer Programming operation,
the device returns to READ mode.
The Write Buffer Programming Sequence is ABORTED under any of the following conditions:
• 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 operation.
• Writing anything other than the Program to Buffer Flash Command after the specified number of
“data load” cycles.
The ABORT condition is indicated by DQ1 = 1, DQ7 = DATA# (for the “last address location loaded”),
DQ6 = TOGGLE, DQ5 = 0. This indicates that the Write Buffer Programming Operation was ABORTED.
This Data Sheet may be revised by subsequent versions
21
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc.,
Rev. A, Issue Date: 2009/3/20
www.eonssi.com