28F640L30, 28F128L30, 28F256L30
8.2.2.2
Synchronous read to write operation transition
W21 - t
W22 - t
VHWL
CHWL
The AC parameters W21 (tVHWL- ADV# High to WE# Low) and W22 (tCHWL -Clock high to
WE# low) are required when the device is in a synchronous mode and clock is active. A write bus
cycle consists of two parts:
• the host provides an address to the flash device; and
• the host then provides data to the flash device.
The flash device in turn binds the received data with the received address. When operating
synchronously (RCR.15 = 0), the address of a write cycle may be provided to the flash by the first
active clock edge with ADV# low, or rising edge of ADV# as long as the applicable cycle
separation conditions are met between each cycle.
If neither a clock edge nor a rising ADV# edge is used to provide a new address at the beginning of
a write cycle (the clock is stopped and ADV# is low), the address may also be provided to the flash
device by holding the address bus stable for the required amount of time (W5, tAVWH) before the
rising WE# edge.
Alternatively, the host may choose not to provide an address to the flash device during subsequent
write cycles (if ADV# is high and only CE# or WE# is toggled to separate the prior cycle from the
current write cycle). In this case, the flash device will use the most recently provided address from
the host.
Refer to Figure 22, “Write to Asynchronous Read Timing” on page 62, Figure 23, “Synchronous
Read to Write Timing” on page 62, and Figure 24, “Write to Synchronous Read Timing” on
page 63, for representation of these timings.
8.2.3
Read Operation During Buffered Programming Flowchart
The multi-partition architecture of the device allows background programming (or erasing) to
occur in one partition while data reads (or code execution) take place in another partition.
To perform a read while buffered programming operation, first issue a Buffered Program set up
command in a partition. When a read operation occurs in the same partition after issuing a setup
command, Status Register data will be returned, regardless of the read mode of the partition prior to
issuing the setup command.
To read data from a block in other partition and the other partition already in read array mode, a
new block address must be issued. However, if the other partition is not already in read array mode,
issuing a read array command will cause the buffered program operation to abort and a command
sequence error would be posted in the Status Register. See Figure 38, “Read While Buffered
Programming Flowchart” on page 82 for more details.
Note: Simultaneous read-while-Buffered EFP is not supported.
Datasheet
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