Information

28.4.10.7.1 Suspending an Erase Flash Sector Operation
To suspend an Erase Flash Sector operation set the FCNFG[ERSSUSP] bit (see Flash
Configuration Field Description) when CCIF is clear and the CCOB command field holds
the code for the Erase Flash Sector command. During the Erase Flash Sector operation
(see Erase Flash Sector Command), the FTFL samples the state of the ERSSUSP bit at
convenient points. If the FTFL detects that the ERSSUSP bit is set, the Erase Flash
Sector operation is suspended and the FTFL sets CCIF. While ERSSUSP is set, all writes
to FTFL registers are ignored except for writes to the FSTAT and FCNFG registers.
If an Erase Flash Sector operation effectively completes before the FTFL detects that a
suspend request has been made, the FTFL clears the ERSSUSP bit prior to setting CCIF.
When an Erase Flash Sector operation has been successfully suspended, the FTFL sets
CCIF and leaves the ERSSUSP bit set. While CCIF is set, the ERSSUSP bit can only be
cleared to prevent the withdrawal of a suspend request before the FTFL has
acknowledged it.
28.4.10.7.2 Resuming a Suspended Erase Flash Sector Operation
If the ERSSUSP bit is still set when CCIF is cleared to launch the next command, the
previous Erase Flash Sector operation resumes. The FTFL acknowledges the request to
resume a suspended operation by clearing the ERSSUSP bit. A new suspend request can
then be made by setting ERSSUSP. A single Erase Flash Sector operation can be
suspended and resumed multiple times.
There is a minimum elapsed time limit between the request to resume the Erase Flash
Sector operation (CCIF is cleared) and the request to suspend the operation again
(ERSSUSP is set). This minimum time period is required to ensure that the Erase Flash
Sector operation will eventually complete. If the minimum period is continually violated,
i.e. the suspend requests come repeatedly and too quickly, no forward progress is made
by the Erase Flash Sector algorithm. The resume/suspend sequence runs indefinitely
without completing the erase.
28.4.10.7.3 Aborting a Suspended Erase Flash Sector Operation
The user may choose to abort a suspended Erase Flash Sector operation by clearing the
ERSSUSP bit prior to clearing CCIF for the next command launch. When a suspended
operation is aborted, the FTFL starts the new command using the new FCCOB contents.
Note
Aborting the erase leaves the bitcells in an indeterminate,
partially-erased state. Data in this sector is not reliable until a
new erase command fully completes.
Flash Operation in Low-Power Modes
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
634 Freescale Semiconductor, Inc.