Information

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.
DEPART
Data flash
EEPROM backup
FlexRAM
EEESIZE
Unavailable
EEPROM partition
FlexNVM
FlexRAM base
address
FlexNVM base
address
Figure 28-30. FlexRAM to FlexNVM Memory Mapping
28.4.2.3 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.
When configured for EEPROM use, writes to an unprotected location in FlexRAM
invokes the EEPROM file system to program a new EEPROM data record in the
EEPROM backup memory in a round-robin fashion. As needed, the EEPROM file
system identifies the EEPROM backup sector that is being erased for future use and
partially erases that EEPROM backup sector. After a write to the FlexRAM, the
FlexRAM is not accessible until the FSTAT[CCIF] bit is set. The FCNFG[EEERDY] bit
will also be set. If enabled, the interrupt associated with the FSTAT[CCIF] bit can be
used to determine when the FlexRAM is available for read or write access.
Functional Description
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
520 Freescale Semiconductor, Inc.