After clearing CCIF to launch the Erase All Execute-only Segments command, the flash
memory module erases all program flash execute-only segments, then verifies that all
segments are erased.
If the flash memory module verifies that all segments were properly erased, flash access
control is disabled until the next reset or, after programming any of the execute-only
segments, the Read 1s All Execute-only Segments command is executed and fails with
the FSTAT[MGSTAT0] bit set. The Erase All Execute-only Segments command aborts if
any XA controlled segment is protected. If the erase-verify fails, the FSTAT[MGSTAT0]
bit is set. The CCIF flag is set after the Erase All Execute-only Segments operation
completes.
Access control determined by the contents of the FXACC registers will not block
execution of the Erase All Execute-only Segments command. While all XA controlled
segments will be erased, the program flash IFR space containing the Program Once
XACC fields will not be erased and, therefore, the contents of the Program Once XACC
fields will not change. The contents of the FXACC registers will not be impacted by the
execution of the Erase All Execute-only Segments command.
Table 29-37. Erase All Execute-only Segments Command Error Handling
Error Condition Error Bit
Command not available in current mode/security FSTAT[ACCERR]
Sector size is larger than segment size FSTAT[ACCERR]
Any XA controlled segment in the program flash memory is protected FSTAT[FPVIOL]
Any errors have been encountered during the verify operation FSTAT[MGSTAT0]
29.4.12 Security
The flash memory module provides security information to the MCU based on contents
of the FSEC security register.
The MCU then limits access to flash memory resources as defined in the device's Chip
Configuration details. During reset, the flash memory module initializes the FSEC
register using data read from the security byte of the Flash Configuration Field (see Flash
Configuration Field Description).
The following fields are available in the FSEC register. The settings are described in the
Flash Security Register (FTFA_FSEC) details.
Flash security features are discussed further in AN4507: Using the Kinetis Security and
Flash Protection Features . Note that not all features described in the application note are
available on this device.
Chapter 29 Flash Memory Module (FTFA)
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 677
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