AM29LV640MH SPANSION [SPANSION], AM29LV640MH Datasheet - Page 40

• Manufacturer Part Number: AM29LV640MH
• Description: 64 Megabit (4 M x 16-Bit/8 M x 8-Bit) MirrorBit 3.0 Volt-only Uniform Sector Flash Memory with VersatileI/O Control
• Manufacturer: SPANSION [SPANSION]

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
38
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
Figure 9. Toggle Bit Algorithm
Reset Command
Complete, Write
Read DQ7–DQ0
Read DQ7–DQ0
Read DQ7–DQ0
Program/Erase
Operation Not
Toggle Bit
Toggle Bit
DQ5 = 1?
= Toggle?
= Toggle?
START
D A T A S H E E T
Twice
Am29LV640MH/L
Yes
Yes
Yes
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
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. See also the
section. Figure 21 shows the toggle bit timing diagram.
Operation Complete
No
No
Program/Erase
RY/BY#: Ready/Busy#
Table 12
December 14, 2005
to compare out-
sub-