A d v a n c e I n f o r m a t i o n
Sector Erase and Program Suspend Operation Mechanics
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 command sequences). Writing the
Sector Erase and Program command during the Sector Erase time-out results in
immediate termination of the time-out period and suspension of the erase oper-
ation. 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 program operations in sectors not being erased. Any other com-
mand written during the Erase Suspend mode is ignored, except for the Sector
Erase and Program Resume command. Writing the Erase and Program Resume
command resumes the sector erase operation. The bank address of the erase
suspended bank is required when writing this command
If the Sector Erase and Program Suspend command is written during a program-
ming operation, the device suspends programming operations and allows only
read operations in sectors not selected for programming. Further nesting of either
erase or programming operations is not permitted. Table 18 summarizes permis-
sible operations during Erase and Program Suspend. (A busy sector is one that is
selected for programming or erasure.):
Table 18. 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 command 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 suspended read mode (pseudo-read mode),
at which time the user can read or program from a sector that is not erase sus-
pended. 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.
Polling DQ6 on two immediately consecutive reads from a given address provides
the system with the ability to determine if the device is in Erase or Program Sus-
pend. Before the device enters Erase or Program Suspend, the DQ6 pin toggles
between two immediately consecutive reads from the same address. After the
device has entered Erase suspend, DQ6 stops toggling between two immediately
consecutive reads to the same address. During the Sector Erase operation and
also in Erase suspend mode, two immediately consecutive readings from the
erase-suspended sector causes DQ2 to toggle. DQ2 does not toggle if reading
from a non-busy (non-erasing) sector (stored data is read). No bits are toggled
during program suspend mode. Software must keep track of the fact that the de-
vice is in a suspended mode.
After entering the erase-suspend-read mode, the system may read or program
within any non-suspended sector:
A read operation from the erase-suspended bank returns polling data during
the first 8 µs after the erase suspend command is issued; read operations
thereafter return array data. Read operations from the other bank return
array data with no latency.
March 22, 2004 30606B0
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