MC908AZ32ACFUE Datasheet, PDF (51/324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 5
EEPROM
5.1 Introduction
This section describes the 512 bytes of electrically erasable programmable read-only memory (EEPROM)
residing at address range $0800 to $09FF.
5.2 Features
Features of the EEPROM include the following:
• 512 bytes Nonvolatile Memory
• Byte, Block, or Bulk Erasable
• Nonvolatile EEPROM Configuration and Block Protection Options
• On-chip Charge Pump for Programming/Erasing
• Security Option
• AUTO Bit Driven Programming/Erasing Time Feature
5.3 EEPROM Register Summary
The EEPROM Register Summary is shown in Figure 5-1.
5.4 Functional Description
The 512 bytes of EEPROM are located at $0800-$09FF and can be programmed or erased without an
additional external high voltage supply. The program and erase operations are enabled through the use
of an internal charge pump. For each byte of EEPROM, the write/erase endurance is 10,000 cycles.
5.4.1 EEPROM Configuration
The 8-bit EEPROM Nonvolatile Register (EENVR) and the 16-bit EEPROM Timebase Divider Nonvolatile
Register (EEDIVNVR) contain the default settings for the following EEPROM configurations:
• EEPROM Timebase Reference
• EEPROM Security Option
• EEPROM Block Protection
EENVR and EEDIVNVR are nonvolatile EEPROM registers. They are programmed and erased in the
same way as EEPROM bytes. The contents of these registers are loaded into their respective volatile
registers during a MCU reset. The values in these read/write volatile registers define the EEPROM
configurations.
MC68HC908AZ32A Data Sheet, Rev. 2
Freescale Semiconductor
51