Rainbow Electronics AT45DB642 - Manual (Page 15)

15 AT45DB321E [PRELIMINARY DATASHEET]
8784B–DFLASH–11/2012
6.10 Program/Erase Suspend (1)
In some code and data storage applications, it may not be possible for the system to wait the milliseconds required for
the Flash memory to complete a program or erase cycle. The Program/Erase Suspend command allows a program or
erase operation in progress to a particular 64KB sector of the main memory array to be suspended so that other device
operations can be performed.
Example: By suspending an erase operation to a particular sector, the system can perform functions such as a
program or read operation within a different 64KB sector. Other device operations, such as Read Status
Register, can also be performed while a program or erase operation is suspended.
To perform a Program/Erase Suspend, an opcode of B0h must be clocked into the device. No address bytes need to be
clocked into the device, and any data clocked in after the opcode will be ignored. When the CS pin is deasserted, the
program or erase operation currently in progress will be suspended within a time of t
SUSP
. One of the Program Suspend
bits (PS1 or PS2) or the Erase Suspend bit (ES) in the Status Register will then be set to the Logic 1 state. In addition,
the RDY/BUSY bit in the Status Register will indicate that the device is ready for another operation.
Read operations are not allowed to a 64KB sector that has had its program or erase operation suspended. If a read is
attempted to a suspended sector, then the device will output undefined data. Therefore, when performing a Continuous
Array Read operation and the device's internal address counter increments and crosses the sector boundary to a
suspended sector, the device will then start outputting undefined data continuously until the address counter increments
and crosses a sector boundary to an unsuspended sector.
A program operation is not allowed to a sector that has been erase suspended. If a program operation is attempted to an
erase suspended sector, then the program operation will abort.
During an Erase Suspend, a program operation to a different 64KB sector can be started and subsequently suspended.
This results in a simultaneous Erase Suspend/Program Suspend condition and will be indicated by the states of both the
ES and PS1 or PS2 bits in the Status Register being set to a Logic 1.
If a Reset command is performed, or if the RESET pin is asserted while a sector is erase suspended, then the suspend
operation will be aborted and the contents of the sector will be left in an undefined state. However, if a reset is performed
while a page is program or erase suspended, the suspend operation will abort but only the contents of the page that was
being programmed or erased will be undefined; the remaining pages in the 64KB sector will retain their previous
contents.
Note: 1. Refer to the errata regarding Program/Erase Suspend feature on page 70 .