am49lv128bm Meet Spansion Inc., am49lv128bm Datasheet - Page 36

• Manufacturer Part Number: am49lv128bm
• Description: Stacked Multi-chip Package Mcp ,128 Megabit 8 M ? 16-bit ,uniform Sector Flash Memory And 32 Mbit 2 M ? 16-bit Pseudo-static Ram With Page Mode Featuring Mirrorbit Technology,supplemental Datasheet
• Manufacturer: Meet Spansion Inc.

Suspend mode. Toggle Bit I may be read at any ad-
dress, 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 op-
eration, 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 approxi-
mately 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 se-
lected sectors that are protected.
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 de-
vice enters the Erase Suspend mode, DQ6 stops toggling.
However, the system must also use DQ2 to determine
which sectors are erasing or erase-suspended. Alterna-
tively, the system can use DQ7 (see the subsection on
DQ7: Data# Polling).
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.
DQ6 also toggles during the erase-suspend-program
mode, and stops toggling once the Embedded Pro-
gram algorithm is complete.
Table 10 shows the outputs for Toggle Bit I on DQ6.
Figure 9 shows the toggle bit algorithm. Figure 21 in
the “AC Characteristics” section shows the toggle bit
timing diagrams. Figure 22 shows the differences be-
tween DQ2 and DQ6 in graphical form. See also the
subsection on DQ2: Toggle Bit II.
DQ2: Toggle Bit II
The “Toggle Bit II” on DQ2, when used with DQ6, indi-
cates 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 have been selected for era-
sure. (The system may use either OE# or CE# to con-
trol the read cycles.) But DQ2 cannot distinguish
34
Figure 8. Toggle Bit Algorithm
Am49LV128BM
whether the sector is actively erasing or is erase-sus-
pended. DQ6, by comparison, indicates whether the
device is actively erasing, or is in Erase Suspend, but
cannot distinguish which sectors are selected for era-
sure. Thus, both status bits are required for sector and
mode information. Refer to Table 10 to compare out-
puts for DQ2 and DQ6.
Figure 9 shows the toggle bit algorithm in flowchart
form, and the section “DQ2: Toggle Bit II” explains the
algorithm. Figure 21 shows the toggle bit timing dia-
gram. Figure 22 shows the differences between DQ2
and DQ6 in graphical form.
Note: The system should recheck the toggle bit even if
DQ5 = “1” because the toggle bit may stop toggling as DQ5
changes to “1.” See the subsections on DQ6 and DQ2 for
more information.
No
Complete, Write
Reset Command
Read DQ7–DQ0
Read DQ7–DQ0
Read DQ7–DQ0
Program/Erase
Operation Not
Toggle Bit
Toggle Bit
DQ5 = 1?
= Toggle?
= Toggle?
START
Twice
Yes
Yes
Yes
Operation Complete
No
No
Program/Erase
June 17, 2004