Information

CAUTION
While different partitions of the FlexNVM block are available,
the intention is that a single partition choice is used throughout
the entire lifetime of a given application. The FlexNVM
partition code choices affect the endurance and data retention
characteristics of the device.
28.4.2.2 EEPROM User Perspective
The EEPROM system is shown in the following figure.
File
system
handler
User access
(effective
EEPROM)
FlexRAM
EEPROM backup
with 1KByte
erase sectors
Figure 28-29. Top Level EEPROM Architecture
To handle varying customer requirements, the FlexRAM and FlexNVM blocks can be
split into partitions as shown in the figure below.
1. EEPROM partition (EEESIZE) — The amount of FlexRAM used for EEPROM
can be set from 0 Bytes (no EEPROM) to the maximum FlexRAM size (see Table
28-2). The remainder of the FlexRAM is not accessible while the FlexRAM is
configured for EEPROM (see Set FlexRAM Function Command). The EEPROM
partition grows upward from the bottom of the FlexRAM address space.
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 28-4).
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.
Chapter 28 Flash Memory Module (FTFL)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 521