Resuming A Suspended Erase Flash Sector Operation; Aborting A Suspended Erase Flash Sector Operation - NXP Semiconductors freescale KV4 Series Reference Manual

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If an Erase Flash Sector operation effectively completes before the flash memory module

detects that a suspend request has been made, the flash memory module clears the

ERSSUSP bit prior to setting CCIF. When an Erase Flash Sector operation has been

successfully suspended, the flash memory module 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 flash memory module has acknowledged it.

32.4.10.5.2 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 flash memory module 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.

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 flash memory module starts the new command using the new

FCCOB contents.

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.

The following figure shows how to suspend and resume the Erase Flash Sector operation.

Freescale Semiconductor, Inc.

KV4x Reference Manual, Rev. 2, 02/2015

Chapter 32 Flash Memory Module (FTFA)