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1 Introduction
Electrically Erasable and Programmable Read Only Memory
(EEPROM) is often used in applications where runtime-
modifiable data needs to be retained after the power has been
removed. Although the Qorivva MPC55xx, MPC56xx, and
MPC57xx family of microcontrollers do not include
EEPROM, the functionality of this memory type can be
emulated with the flash memory that is available. This
document describes the basic principles behind using Qorivva
flash memory for EEPROM emulation, and provides some
insight on the functionality of NXP EEPROM emulation
drivers.
2
EEPROM and Flash Memory
Characteristics
EEPROM and flash memory are both non-volatile memories,
meaning they retain their data after power has been removed.
They are both composed of an array of memory cells, where
each memory cell holds one or more bits of information. In
some designs, multiple cells combine to form a single bit.
For the NOR flash memory on Qorivva devices, each memory
cell stores one bit of information. In EEPROM and flash
memories where each memory cell holds one bit of
information, the default, erased state of the memory cell reads
NXP Semiconductors
Document Number: AN4868
Application Note
Rev. 2, 03/2017
EEPROM Emulation with Qorivva
MPC55xx, MPC56xx, and MPC57xx
Microcontrollers
by: David McDaid
Contents
1 Introduction................................................................1
2 EEPROM and Flash Memory
Characteristics............................................................1
3 EEPROM Emulation Using Flash
Memory.....................................................................2
4 Read-While-Write.....................................................9
5 Software Implementation and
Variations.............................................. ..................10
6 Program-Erase Endurance....................................... 13
