COTS PEM
BOOT SECTOR FLASH
Austin Semiconductor, Inc.
AS29LV016J
If a program address falls within a protected sector, DQ6
toggles for approximately 1 µs after the program command
sequence is written, then returns to reading array data.
RY/BY#: READY/BUSY#
The RY/BY# is a dedicated, open-drain output pin that
indicates whether an EmbeddedAlgorithm is in progress
or complete. The RY/BY# status is valid after the rising
edge of the final WE# pulse in the command sequence.
Since RY/BY# is an open-drain output, several RY/BY#
pins can be tied together in parallel with a pull-up resistor
to VCC.
DQ6 also toggles during the erase-suspend-program
mode, and stops toggling once the Embedded Program
algorithm is complete.
Table 10 on page 25 shows the outputs for Toggle Bit I
on DQ6. Figure 6, on page 24 shows the toggle bit
algorithm in flowchart form, and Reading Toggle Bits DQ6/
DQ2 on page 24 explains the algorithm. Figure 19, on
page 34 shows the toggle bit timing diagrams. Figure
20, on page 5 shows the differences between DQ2 and
DQ6 in graphical form. See also the subsection on DQ2:
Toggle Bit II below.
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 10 on page 25 shows the outputs for RY/BY#.
Figures: Figure 12, on page 29, Figure 13, on page 30,
Figure 16, on page 33 and Figure 17, on page 33 shows
RY/BY# for read, reset, program, and erase operations,
respectively.
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.
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.
DQ2 toggles when the system reads at addresses within
those sectors that have been 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 for erasure. Thus, both status
bits are required for sector and mode information. Refer
to Table 10 on page 25 to compare outputs for DQ2 and
DQ6.
During an Embedded Program or Erase algorithm
operation, successive read cycles 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 algorithm erases the unprotected sectors, and
ignores the selected sectors that are protected.
Figure 6, on page 24 shows the toggle bit algorithm in
flowchart form, and the section Reading Toggle Bits DQ6/
DQ2 on page 24 explains the algorithm. See also the
DQ6: Toggle Bit I subsection. Figure 19, on page 34 shows
the toggle bit timing diagram. Figure 20, on page 35 shows
the differences between DQ2 and DQ6 in graphical form.
The system can use DQ6 and DQ2 together to determine
whether a sector is actively 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 enters the Erase Suspend mode, DQ6 stops
toggling. However, the system must also use DQ2 to
determine which sectors are erasing or erase-suspended.
Alternatively, the system can use DQ7 (see the
subsection on DQ7: Data# Polling on page 22).
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
AS29LV016J
Rev. 0.0 02/09
23
AUSTIN [ AUSTIN SEMICONDUCTOR ]
