MC68HC12 Datasheet, PDF (125/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

EEPROM Memory
EEPROM Programmer’s Model
9.4 EEPROM Programmer’s Model
The EEPROM module consists of two separately addressable sections.
The first is an eight-byte memory mapped control register block used for
control, testing and configuration of the EEPROM array. The second
section is the EEPROM array itself.
At reset, the eight-byte register section starts at address $00EC and the
EEPROM array is located from addresses $0800 to $0FFF. Registers
$00EC-$00ED are reserved.
Read/write access to the memory array section can be enabled or
disabled by the EEON control bit in the INITEE register ($0012). This
feature allows the access of memory mapped resources that have lower
priority than the EEPROM memory array. EEPROM control registers can
be accessed regardless of the state of EEON. Any EEPROM erase or
program operation already in progress will not be affected by the change
of EEON state. For information on re-mapping the register block and
EEPROM address space, refer to Operating Modes.
CAUTION:
It is strongly recommended to discontinue program/erase operations
during WAIT (when EESWAI=1) or STOP modes since all
program/erase activities will be terminated abruptly and considered
unsuccessful.
For lowest power consumption during WAIT mode, it is advised to turn
off EEPGM.
The EEPROM module contains an extra word called SHADOW word
which is loaded at reset into the EEMCR, EEDIVH and EEDIVL
registers. To program the SHADOW word, when in special modes
(SMODN=0), the NOSHW bit in EEMCR register must be cleared.
Normal programming routines are used to program the SHADOW word
which becomes accessible at address $0FC0-$0FC1 when NOSHW is
cleared. At the next reset the SHADOW word data is loaded into the
EEMCR, EEDIVH and EEDIVL registers. The SHADOW word can be
protected from being programmed or erased by setting the SHPROT bit
of EEPROT register.
MC68HC912DT128A — Rev 4.0
MOTOROLA
EEPROM Memory
Technical Data
125