S912XHZ512F1VAG Datasheet, PDF (175/978 Pages) Freescale Semiconductor, Inc – Covers MC9S12XHZ384, MC9S12XHZ256

Chapter 4
4 Kbyte EEPROM Module (S12XEETX4KV2)
4.1 Introduction
This document describes the EETX4K module which includes a 4 Kbyte EEPROM (nonvolatile) memory.
The EEPROM memory may be read as either bytes, aligned words, or misaligned words. Read access time
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. Cumulative programming of bits within a word is not allowed.
4.1.1 Glossary
Command Write Sequence — A three-step MCU instruction sequence to execute built-in algorithms
(including program and erase) on the EEPROM memory.
4.1.2 Features
• 4 Kbytes of EEPROM memory divided into 1024 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
4.1.3 Modes of Operation
Program, erase and erase verify operations (please refer to Section 4.4.1, “EEPROM Command
Operations” for details).
MC9S12XHZ512 Data Sheet, Rev. 1.06
Freescale Semiconductor
175