P30-65nm SBC
Read SR command (70h), which would be interpreted by the internal state machines as
Buffer Word Count.
On the next write, a word count is written to the device at the buffer address. This tells
the device how many data words will be written to the buffer, up to the maximum size
of the buffer.
On the next write, a device start address is given along with the first data to be written
to the flash memory array. Subsequent writes provide additional device addresses and
data. All data addresses must lie within the start address plus the word count.
Optimum programming performance and lower power usage are obtained by aligning
the starting address at the beginning of a 256-word boundary (A[8:1] = 0x00).
Note:
If a misaligned address range is issued during buffered programming, the program
region must also be within an 256-word aligned boundary.
After the last data is written to the buffer, the Buffered Programming Confirm command
must be issued to the original block address. The WSM begins to program buffer
contents to the flash memory array. If an error occurs while writing to the array, the
device stops programming, and SR[7,4] are set, indicating a programming failure.
When Buffered Programming has completed, additional buffer writes can be initiated by
issuing another Buffered Programming Setup command and repeating the buffered
program sequence. Buffered programming may be performed with VPP = VPPL or VPPH
(see Section 13.2, “Operating Conditions” on page 45 for limitations when operating
the device with VPP = VPPH).
If an attempt is made to program past an erase-block boundary using the Buffered
Program command, the device aborts the operation. This generates a command
sequence error, and SR[5,4] are set.
If Buffered programming is attempted while VPP is at or below VPPLK, SR[4,3] are set.
If any errors are detected that have set Status Register bits, the Status Register should
be cleared using the Clear Status Register command.
8.3
Buffered Enhanced Factory Programming
Buffered Enhanced Factory Programing (BEFP) speeds up the flash programming
perforamnce. The enhanced programming algorithm used in BEFP eliminates traditional
programming elements that drive up overhead in device programmer systems.
BEFP consists of three phases: Setup, Program/Verify, and Exit (see Figure 37, “BEFP
Flowchart” on page 78). It uses a write buffer to spread up the program performance
across 256 data words. Verification occurs in the same phase as programming to
accurately program the flash memory cell to the correct bit state.
A single two-cycle command sequence programs the entire block of data. This
enhancement eliminates three write cycles per buffer: two commands and the word
count for each set of 256 data words. Host programmer bus cycles fill the device’s write
buffer followed by a status check. SR.0 indicates when data from the buffer has been
programmed into sequential flash memory array locations.
Following the buffer-to-flash array programming sequence, the Write State Machine
(WSM) increments internal addressing to automatically select the next 256-word array
boundary. This aspect of BEFP saves host programming equipment the address-bus
setup overhead.
With adequate continuity testing, programming equipment can rely on the WSM’s
internal verification to ensure that the device has programmed properly. This eliminates
the external post-program verification and its associated overhead.
Datasheet
25
Apr 2010
OrderNumber:208033-02
MICRON [ MICRON TECHNOLOGY ]
