MC9S12XDP512 Data Sheet, Rev. 2.17
Freescale Semiconductor
1039
Chapter 25
2 Kbyte EEPROM Module (S12XEETX2KV1)
25.1
Introduction
This document describes the EETX2K module which includes a 2Kbyte EEPROM (nonvolatile) memory.
TheEEPROMmemorymaybereadaseitherbytes,alignedwords,ormisalignedwords.Readaccesstime
is one bus cycle for bytes and aligned words, and two bus cycles for misaligned words.
The EEPROM memory is ideal for data storage for single-supply applications allowing for field
reprogramming without requiring external voltage sources for program or erase. Program and erase
functions are controlled by a command driven interface. The EEPROM module supports both block erase
(all memory bytes) and sector erase (4 memory bytes). An erased bit reads 1 and a programmed bit reads
0. The high voltage required to program and erase the EEPROM memory is generated internally. It is not
possible to read from the EEPROM block while it is being erased or programmed.
CAUTION
An EEPROM word (2 bytes) must be in the erased state before being
programmed.Cumulativeprogrammingofbitswithinawordisnotallowed.
25.1.1
Glossary
Command Write Sequence
— A three-step MCU instruction sequence to execute built-in algorithms
(including program and erase) on the EEPROM memory.
25.1.2
Features
2 Kbytes of EEPROM memory divided into 512 sectors of 4 bytes
Automated program and erase algorithm
Interrupts on EEPROM command completion and command buffer empty
Fast sector erase and word program operation
2-stage command pipeline
Sector erase abort feature for critical interrupt response
Flexible protection scheme to prevent accidental program or erase
Single power supply for all EEPROM operations including program and erase
25.1.3
Modes of Operation
Program, erase and erase verify operations (please refer to
Section 25.4.1, “EEPROM Command
Operations”
for details).