am42bds6408h Meet Spansion Inc., am42bds6408h Datasheet - Page 47

• Manufacturer Part Number: am42bds6408h
• Description: Cmos 1.8 Volt-only Simultaneous Read/write, Burst Mode Flash Memory, And 8 Mbit 512 K X 16-bit Sram
• Manufacturer: Meet Spansion Inc.

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.
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.
October 23, 2003
No
Figure 7. Toggle Bit Algorithm
Read Byte Twice
DQ6 = Toggle?
DQ6 = Toggle?
Address = VA
Address = VA
Adrdess = VA
(DQ7-DQ0)
(DQ7-DQ0)
(DQ7-DQ0)
Read Byte
Read Byte
DQ5 = 1?
START
FAIL
Yes
Yes
Yes
A D V A N C E
No
No
PASS
Am42BDS6408H
I N F O R M A T I O N
DQ2 toggles when the system reads at addresses
within those sectors that have been selected for era-
sure. But DQ2 cannot distinguish whether the sector is
actively erasing or is erase-suspended. DQ6, by com-
parison, 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 informa-
tion. Refer to
page 46
See the following for additional information:
“Toggle Bit Algorithm,” on page 45, “DQ6: Toggle Bit I”
o n p a g e 4 4 , F i g u r e 3 8 , “ To g g l e B i t T i m i n g s
(During Embedded Algorithm),” on page
Table 17, “DQ6 and DQ2 Indications,” on page
to compare outputs for DQ2 and DQ6.
Table 17, “DQ6 and DQ2 Indications,” on
Figure 7,
72, and
46.
45