Numonyx™ StrataFlash® Cellular Memory (M18)
Note:
Issuing the Read Status Register command to another partition switches that partition’s
read mode to Read Status Register mode, thereby allowing programming progress to
be monitored from that partition’s address.
Single-Word Programming is supported in Control mode only. The array address
specified must be in the A-half of the programming region.
During programming, the Status Register indicates a busy status (SR7 = 0). Upon
completion, the Status Register indicates a ready status (SR7 = 1). The Status Register
should be checked for any errors, then cleared.
The only valid commands during programming are Read Array, Read Device
Information, CFI Query, Read Status and Program Suspend. After programming has
finished, any valid command can be issued.
Note:
Issuing the Read Array, Read Device Information, or CFI Query command to a partition
that is actively programming causes subsequent reads from that partition to output
invalid data. Valid data is output only after the program operation has finished.
Standby power levels are not realized until the programming operation has finished.
Asserting RST# immediately aborts the programming operation, and array contents at
the addressed location are indeterminate. The addressed block should be erased, and
the data re-programmed.
9.6.2
Note:
Buffered Programming
Buffered Programming programs multiple words simultaneously into the flash memory
array. Data is first written to a write buffer and then programmed into the flash
memory array in buffer-size increments. This can significantly reduce the effective
word-write time. Section 6.0, “Flow Charts” on page 41 contains a flow chart of the
buffered-programming operation.
Optimal performance and power consumption is realized only by aligning the start
address on 32-word boundaries, e.g., A[4:0] = 00000b. Crossing a 32-word boundary
during a Buffered Programming operation can cause the programming time to double.
Buffered Programming is supported in both Control mode and Object mode. In Object
mode, the region must be programmed only once between erases. However in Control
mode, the region may be programmed multiple times.
Caution:
When using the Buffered Program command in Object mode, the start address
must be aligned to the 512-word buffer boundary. In Control mode, the
programming array address specified must be in the A-half of the
programming region.
First issue the Read Status command to the desired partition. The read mode of the
addressed partition is changed to Read Status Register mode.
Poll SR7 to determine write-buffer availability (0 = not available, 1 = available). If the
write buffer is not available, re-issue the Read Status command and check SR7; repeat
until SR7 = 1.
If desired issue a Read Array command to the desired partition to change the read
mode of the partition to Array reads.
To perform a buffered programming operation, issue the Buffered Program setup
command at the desired starting address. Next, issue a word count at the desired
starting address. The word count is the total number of words to be written into the
write buffer, minus one. This value can range from 0000h (one word) up to a maximum
of 01FFh (512 words). Exceeding the allowable range causes the operation to abort.
April 2008
309823-10
Datasheet
89
NUMONYX [ NUMONYX B.V ]
