
Numonyx StrataFlash Embedded Memory (P33)
Datasheet
November 2007
60
Order Number: 314749-05
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.
11.3.3.1
BEFP Requirements and Considerations
BEFP requirements:
Case temperature: TC = 25 °C ± 5 °C
VCC within specified operating range
VPP driven to VPPH
Target block unlocked before issuing the BEFP Setup and Confirm commands
The first-word address for the block to be programmed must be held constant from
the setup phase through all data streaming into the target block, until transition to
the exit phase is desired
The first-word address must align with the start of an array buffer boundary1
BEFP considerations:
For optimum performance, cycling must be limited below 100 erase cycles per
block2
BEFP programs one block at a time; all buffer data must fall within a single block3
BEFP cannot be suspended
Programming to the flash memory array can occur only when the buffer is full4
Note:
1.
Word buffer boundaries in the array are determined by A[4:0] (0x00 through 0x1F). The alignment start point is A[4:0] =
0x00.
2.
Some degradation in performance may occur if this limit is exceeded, but the internal algorithm continues to work
properly.
3.
If the internal address counter increments beyond the block's maximum address, addressing wraps around to the
beginning of the block.
4.
If the number of words is less than 32, remaining locations must be filled with 0xFFFF.
11.3.3.2
BEFP Setup Phase
After receiving the BEFP Setup and Confirm command sequence, Status Register bit
SR[7] (Ready) is cleared, indicating that the WSM is busy with BEFP algorithm startup.
A delay before checking SR[7] is required to allow the WSM enough time to perform all
of its setups and checks (Block-Lock status, VPP level, etc.). If an error is detected,
SR[4] is set and BEFP operation terminates. If the block was found to be locked, SR[1]
is also set. SR[3] is set if the error occurred due to an incorrect VPP level.
Note:
Reading from the device after the BEFP Setup and Confirm command sequence outputs
Status Register data. Do not issue the Read Status Register command; it will be
interpreted as data to be loaded into the buffer.
11.3.3.3
BEFP Program/Verify Phase
After the BEFP Setup Phase has completed, the host programming system must check
SR[7,0] to determine the availability of the write buffer for data streaming. SR[7]
cleared indicates the device is busy and the BEFP program/verify phase is activated.
SR[0] indicates the write buffer is available.
Two basic sequences repeat in this phase: loading of the write buffer, followed by buffer
data programming to the array. For BEFP, the count value for buffer loading is always
the maximum buffer size of 32 words. During the buffer-loading sequence, data is