A d v a n c e I n f o r m a t i o n
If the output is low (Busy), the device is actively erasing or programming. (This
includes programming in the Erase Suspend mode.) If the output is high (Ready),
the device is ready to read array data (including during the Erase Suspend
mode), or is in the standby mode.
Table 6 on page 31 shows the outputs for RY/BY#. Figure 13, on page 37, Figure
14, on page 38, Figure 17, on page 42, and Figure 18, on page 43 shows RY/BY#
for read, reset, program, and erase operations, respectively.
DQ6: Toggle Bit I
Toggle Bit I on DQ6 indicates whether an Embedded Program or Erase algorithm
is in progress or complete, or whether the device has entered the Erase Suspend
mode. Toggle Bit I may be read at any address, and is valid after the rising edge
of the final WE# pulse in the command sequence (prior to the program or erase
operation), and during the sector erase time-out.
During an Embedded Program or Erase algorithm operation, successive read cy-
cles to any address cause DQ6 to toggle. (The system may use either OE# or CE#
to control the read cycles.) When the operation is complete, DQ6 stops toggling.
After an erase command sequence is written, if all sectors selected for erasing
are protected, DQ6 toggles for approximately 100 µs, then returns to reading
array data. If not all selected sectors are protected, the Embedded Erase algo-
rithm erases the unprotected sectors, and ignores the selected sectors that are
protected.
The system can use DQ6 and DQ2 together to determine whether a sector is ac-
tively erasing or is erase-suspended. When the device is actively erasing (that is,
the Embedded Erase algorithm is in progress), DQ6 toggles. When the device en-
ters the Erase Suspend mode, DQ6 stops toggling. However, the system must
also use DQ2 to determine which sectors are erasing or erase-suspended. Alter-
natively, the system can use DQ7 (see the subsection on DQ7: Data# Polling‚ on
page 26).
If a program address falls within a protected sector, DQ6 toggles for approxi-
mately 1 µs after the program command sequence is written, then returns to
reading array data.
DQ6 also toggles during the erase-suspend-program mode, and stops toggling
once the Embedded Program algorithm is complete.
Table 6 on page 31 shows the outputs for Toggle Bit I on DQ6. Figure 6, on page
30 shows the toggle bit algorithm. Figure 20, on page 44 shows the toggle bit
timing diagrams. Figure 21, on page 45 shows the differences between DQ2 and
DQ6 in graphical form. See also the subsection on DQ2: Toggle Bit II‚ on
page 28.
DQ2: Toggle Bit II
The Toggle Bit II on DQ2, when used with DQ6, indicates whether a particular
sector is actively erasing (that is, the Embedded Erase algorithm is in progress),
or whether that sector is erase-suspended. Toggle Bit II is valid after the rising
edge of the final WE# pulse in the command sequence.
DQ2 toggles when the system reads at addresses within those sectors that are
selected for erasure. (The system may use either OE# or CE# to control the read
cycles.) But DQ2 cannot distinguish whether the sector is actively erasing or is
erase-suspended. DQ6, by comparison, indicates whether the device is actively
erasing, or is in Erase Suspend, but cannot distinguish which sectors are selected
28
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