E S I
E S I
Excel Semiconductor inc.
time-out also applies after each additional sector
erase command. When the time-out period is com-
plete, DQ3 switches from a “0” to a”1”. If the time
between additional sector erase commands from the
system can be assumed to be less than 50us, the
system need not monitor DQ3. See also the Sector
Erase Command Sequence section. After the sector
erase command is written, the system should read
the status of DQ7 (Data# Polling) or DQ6 (Toggle Bit
I) to ensure that the device has accepted the com-
mand sequence, and then read DQ3. If DQ3 is “1”,
the Embedded Erase algorithm has begun; all fur-
ther commands (except Erase Suspend) are ignored
until the erasure operation is complete. If DQ3 is “0”,
the device will accept additional sector erase com-
mands. To ensure the command has been accepted,
the system software should check the status of DQ3
prior to and following each subsequent sector erase
command. If DQ3 is high on the second status
check, the last command might not have been
accepted. In Table 6, DQ3 status operation is well
defined and summarized with other status bits, DQ7,
DQ6, DQ5, and DQ2.
DQ5 ( EXCEEDED TIMING LIMITS )
DQ5 indicates whether the program or erase time
has exceeded a specified internal pulse count limit.
Under these conditions DQ5 produces a “1”, indi-
cating that the program or erase cycle was not suc-
cessfully completed. The device may output a “1”
on DQ5 if the system tries to program a “1” to a
location that was previously programmed to “0”
Only an erase operation can change a “0” back to a
“1”. Under this condition, the device halts the opera-
tion, and when the timing limit has been exceeded,
DQ5 produces a ”1”. Under both these conditions,
the system must write the reset command to return
to the read mode.
DQ3 ( SECTOR ERASE TIMER )
After writing a sector erase command sequence,
the system may read DQ3 to determine whether or
not erasure has begun. (The sector erase time
does not apply to the chip erase command.) If addi-
tional sectors are selected for erasure, the entire
Table 6. Write Operation Status
DQ7
DQ5
(Note 1)
DQ3
DQ2
(Note 2)
RY/
BY#
Status
DQ6
(Note 2)
DQ7#
0
Embedded Program Algorithm
Embedded Erase Algorithm
Toggle
Toggle
0
0
N/A
No toggle
0
0
Standard
Mode
1
Toggle
Toggle
Erase Suspended
Sector
1
No toggle
0
N/A
1
Erase-Suspend-
Read
Erase Sus-
pend Mode
Non-Erase
Suspended Sector
Data
Data
Data
0
Data
N/A
Data
N/A
1
0
Erase-Suspend-Program
DQ7#
Toggle
Notes :
1. DQ5 switches to “1” when an Embedded Program or Embedded Erase operation has exceeded the maximum timing limits. Refer to the
section on DQ5 for more information.
2. DQ7 and DQ2 require a valid address when reading status information. Refer to the appropriate subsection for further details.
24
Rev.0B January 5, 2006
ES29LV400E
EXCELSEMI [ EXCEL SEMICONDUCTOR INC. ]
