Information

flash memory need to be programmed, e.g. during factory programming, the FlexRAM
can be used as the Section Program Buffer for the Program Section command (see
Program Section Command).
When making the FlexRAM available for EEPROM, the flash memory module clears the
FCNFG[EEERDY] and FCNFG[RAMRDY] flags, overwrites the contents of the
FlexRAM allocated for EEPROM with a background pattern of all ones, and copies the
existing EEPROM data from the EEPROM backup record space to the FlexRAM. After
completion of the EEPROM copy-down, the FCNFG[EEERDY] flag is set. When the
FlexRAM is set to function as EEPROM, normal read and write access to the FlexRAM
is available, but writes to the FlexRAM also invoke EEPROM activity. The CCIF flag is
set after the Set FlexRAM Function operation completes.
Table 28-70. Set FlexRAM Function Command Error Handling
Error Condition Error Bit
Command not available in current mode/security FSTAT[ACCERR]
FlexRAM Function Control Code is not defined FSTAT[ACCERR]
FlexRAM Function Control Code is set to make the FlexRAM available for EEPROM, but
FlexNVM is not partitioned for EEPROM
FSTAT[ACCERR]
28.4.12 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 (FTFL_FSEC) details.
Table 28-71. FSEC register fields
FSEC field Description
KEYEN Backdoor Key Access
MEEN Mass Erase Capability
FSLACC Freescale Factory Access
SEC MCU security
Chapter 28 Flash Memory Module (FTFL)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 555