am42bds6408h Meet Spansion Inc., am42bds6408h Datasheet - Page 45

• 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.

WRITE OPERATION STATUS
The device provides several bits to determine the
status of a program or erase operation: DQ2, DQ3,
DQ5, DQ6, and DQ7.
Status,” on page 47
describe the function of these bits. DQ7 and DQ6 each
offers a method for determining whether a program or
erase operation is complete or in progress.
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host
system whether an Embedded Program or Erase algo-
rithm is in progress or completed, or whether a bank is
in Erase Suspend. Data# Polling is valid after the rising
edge of the final WE# pulse in the command sequence.
During the Embedded Program algorithm, the device
outputs on DQ7 the complement of the datum pro-
grammed to DQ7. This DQ7 status also applies to pro-
g r a m m i n g d u r i n g E r a s e S u s p e n d . W h e n t h e
Embedded Program algorithm is complete, the device
outputs the datum programmed to DQ7. The system
must provide the program address to read valid status
information on DQ7. If a program address falls within a
protected sector, Data# Polling on DQ7 is active for
approximately 1 µs, then that bank returns to the read
mode.
During the Embedded Erase algorithm, Data# Polling
produces a “0” on DQ7. When the Embedded Erase
algorithm is complete, or if the bank enters the Erase
Suspend mode, Data# Polling produces a “1” on DQ7.
The system must provide an address within any of the
sectors selected for erasure to read valid status infor-
mation on DQ7.
After an erase command sequence is written, if all
sectors selected for erasing are protected, Data#
Polling on DQ7 is active for approximately 100 µs, then
the bank returns to the read mode. If not all selected
sectors are protected, the Embedded Erase algorithm
erases the unprotected sectors, and ignores the
selected sectors that are protected. However, if the
system reads DQ7 at an address within a protected
sector, the status may not be valid.
Just prior to the completion of an Embedded Program
or Erase operation, DQ7 may change asynchronously
with DQ6–DQ0 while Output Enable (OE#) is asserted
low. That is, the device may change from providing
status information to valid data on DQ7. Depending on
when the system samples the DQ7 output, it may read
the status or valid data. Even if the device has com-
pleted the program or erase operation and DQ7 has
valid data, the data outputs on DQ6-DQ0 may be still
October 23, 2003
and the following subsections
Table 18, “Write Operation
A D V A N C E
Am42BDS6408H
I N F O R M A T I O N
invalid. Valid data on DQ7-DQ0 will appear on succes-
sive read cycles.
Table 18, “Write Operation Status,” on page 47
the outputs for Data# Polling on DQ7.
Polling Algorithm,” on page 43
al g or it h m.
(During Embedded Algorithm),” on page 72
Characteristics section shows the Data# Polling timing
diagram.
Notes:
1. VA = Valid address for programming. During a sector
2. DQ7 should be rechecked even if DQ5 = “1” because
erase operation, a valid address is any sector address
within the sector being erased. During chip erase, a valid
address is any non-protected sector address.
DQ7 may change simultaneously with DQ5.
No
Figure 6. Data# Polling Algorithm
Read DQ7–DQ0
Read DQ7–DQ0
F ig u r e 37 , “ D a t a # Po l lin g T i m in g s
DQ7 = Data?
DQ7 = Data?
Addr = VA
Addr = VA
DQ5 = 1?
START
FAIL
No
Yes
No
shows the Data# Polling
Yes
Yes
Figure 6, “Data#
PASS
in the AC
shows
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