A D V A N C E I N F O R M A T I O N
Figure 5 illustrates the Embedded™ Erase Algorithm,
■ An internal counter monitors the number of erase
pulses initiated and has a maximum value of 5980.
The counter is incremented by one every time an
erase pulse is initiated, regardless of whether or not
that erase pulse is successful. An erase pulse is ter-
minated immediately when the suspend command
is executed. A new erase pulse is initiated when the
resume command is executed (and the counter is
incremented).
using a typical command sequence and bus operation.
Refer to the Erase/Program Operations tables in the
AC Characteristics section for parameters, and to Fig-
ure 22 for timing diagrams.
START
■ Given that 300 successful erase pulses are re-
quired, a successful sector erase operation shall
have a maximum of 5680 erase suspends.
Write Erase
The Sector Erase and Program Suspend command is
ignored if written during the execution of the Chip
Erase operation or Embedded Program Algorithm (but
will reset the chip if written improperly during the com-
mand sequences). Writing the Sector Erase and Pro-
gram command during the Sector Erase time-out
results in immediate termination of the time-out period
and suspension of the erase operation. Once in Erase
Suspend, the device is available for reading (note that
in the Erase Suspend mode, the Reset command is
not required for read operations and is ignored) or pro-
gram operations in sectors not being erased. Any
other command written during the Erase Suspend
mode is ignored, except for the Sector Erase and Pro-
gram Resume command. Writing the Erase and Pro-
gram Resume command resumes the sector erase
operation. The bank address of the erase suspended
bank is required when writing this command
Command Sequence
Data Poll
from System
Embedded
Erase
algorithm
in progress
No
Data = FFh?
Yes
Erasure Completed
Notes:
1. See Tables 18 and 20 for erase command sequence.
If the Sector Erase and Program Suspend command
is written during a programming operation, the device
suspends programming operations and allows only
read operations in sectors not selected for program-
ming. Further nesting of either erase or programming
operations is not permitted. Table 17 summarizes per-
missible operations during Erase and Program Sus-
pend. (A busy sector is one that is selected for
programming or erasure.):
2. See DQ3: Sector Erase Timer for more information.
Figure 5. Erase Operation
Sector Erase and Program Suspend
Command
The Sector Erase and Program Suspend command al-
lows the user to interrupt a Sector Erase or Program
operation and perform data read or programs in a sec-
tor that is not being erased or to the sector where a
programming operation was initiated. This command
is applicable only during the Sector Erase and Pro-
gramming operation, which includes the time-out pe-
riod for Sector Erase.
Table 17. Allowed Operations During
Erase/Program Suspend
Sector
Program Suspend
Erase Suspend
Busy Sector
Program Resume
Erase Resume
Non-busy
sectors
Read Only
Read or Program
When the Sector Erase and Program Suspend com-
mand is written during a Sector Erase operation, the
chip will take between 0.1 µs and 20 µs to actually
suspend the operation and go into the erase sus-
pended read mode (pseudo-read mode), at which time
the user can read or program from a sector that is not
erase suspended. Reading data in this mode is the
same as reading from the standard read mode, except
that the data must be read from sectors that have not
been erase suspended.
Sector Erase and Program Suspend
Operation Mechanics
■ A successful erase pulse has a duration or 1.2 ms
± 20%, depending on the number of previous erase
cycles (among other factors).
■ A successful sector erase operation requires 300
successful erase pulses.
April 8, 2003
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