NXP Semiconductors Kinetis KE1xZ256, Reference Manual

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2. Data flash partition (DEPART) — The amount of FlexNVM memory used for data
flash can be programmed from 0 bytes (all of the FlexNVM block is available for
EEPROM backup) to the maximum size of the FlexNVM block (see
Table 16-4 ).
3. FlexNVM EEPROM partition — The amount of FlexNVM memory used for
EEPROM backup, which is equal to the FlexNVM block size minus the data flash
memory partition size. The EEPROM backup size must be at least 16 times the
EEPROM partition size in FlexRAM.
The partition information (EEESIZE, DEPART) is stored in the data flash IFR and is
programmed using the Program Partition command (see
Program Partition command ).
Typically, the Program Partition command is executed only once in the lifetime of the
device.
Data flash memory is useful for applications that need to quickly store large amounts of
data or store data that is static. The EEPROM partition in FlexRAM is useful for storing
smaller amounts of data that will be changed often.
DE
P
AR
T
Data flash
EEPROM backup
FlexRAM
E
E
E
S
IZ
E
Unavailable
EEPROM partition
FlexNVM
FlexRAM base
address
FlexNVM base
address
Figure 16-8. FlexRAM to FlexNVM Memory Mapping for EEPROM
16.5.3.3 EEPROM implementation overview
Out of reset with the FSTAT[CCIF] bit clear, the partition settings (EEESIZE, DEPART)
are read from the data flash IFR and the EEPROM file system is initialized accordingly.
The EEPROM file system locates all valid EEPROM data records in EEPROM backup
and copies the newest data to FlexRAM. The FSTAT[CCIF] and FCNFG[EEERDY] bits
are set after data from all valid EEPROM data records is copied to the FlexRAM. After
the CCIF bit is set, the FlexRAM is available for read or write access.
Functional Description
Kinetis KE1xZ256 Sub-Family Reference Manual, Rev. 3, 07/2018
314 NXP Semiconductors