Information

FTFL_FCNFG field descriptions (continued)
Field Description
0 FlexRAM is not available for traditional RAM access.
1 FlexRAM is available as traditional RAM only; writes to the FlexRAM do not trigger EEPROM
operations.
0
EEERDY
This flag indicates if the EEPROM backup data has been copied to the FlexRAM and is therefore available
for read access.
During the reset sequence, the EEERDY flag will remain cleared while CCIF is clear and will only set if the
FlexNVM block is partitioned for EEPROM.
0 FlexRAM is not available for EEPROM operation.
1 FlexRAM is available for EEPROM operations where:
• reads from the FlexRAM return data previously written to the FlexRAM in EEPROM mode and
• writes to the FlexRAM clear EEERDY and launch an EEPROM operation to store the written
data in the FlexRAM and EEPROM backup.
28.34.3 Flash Security Register (FTFL_FSEC)
This read-only register holds all bits associated with the security of the MCU and flash
memory module.
During the reset sequence, the register is loaded with the contents of the flash security
byte in the Flash Configuration Field located in program flash memory. The flash basis
for the values is signified by X in the reset value.
Address: 4002_0000h base + 2h offset = 4002_0002h
Bit 7 6 5 4 3 2 1 0
Read KEYEN MEEN FSLACC SEC
Write
Reset
x* x* x* x* x* x* x* x*
* Notes:
x = Undefined at reset.•
FTFL_FSEC field descriptions
Field Description
7–6
KEYEN
Backdoor Key Security Enable
These bits enable and disable backdoor key access to the flash memory module.
00 Backdoor key access disabled
01 Backdoor key access disabled (preferred KEYEN state to disable backdoor key access)
10 Backdoor key access enabled
11 Backdoor key access disabled
Table continues on the next page...
Chapter 28 Flash Memory Module (FTFL)
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
Freescale Semiconductor, Inc.
Preliminary
595
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