MC912DG128A Motorola, MC912DG128A Datasheet - Page 111

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

Program/Erase Operation
Shadow Word Mapping
11-eeprom
MOTOROLA
CAUTION:
A program or erase operation should follow the sequence below if AUTO
bit is clear:
If the AUTO bit is set, steps 4 and 5 can be replaced by a step to poll the
EEPGM bit until it is cleared.
The state machine will not start if an attempt is made to program or erase
a protected location and therefore the EEPGM bit will never clear on that
EEPROM operation. Check for protected status or use a software
timeout to avoid a continuous loop whilst polling the EEPGM bit. If using
a timeout, ensure steps 5 and 6 are still executed.
It is possible to program/erase more bytes or words without intermediate
EEPROM reads, by jumping from step 5 to step 2.
The shadow word is mapped to location $_FC0 and $_FC1 when the
NOSHW bit in EEMCR register is zero. The value in the shadow word is
loaded to the EEMCR, EEDIVH and EEDIVL after reset.
the mapping of each bit from shadow word to the registers.
1. Write BYTE, ROW and ERASE to desired value, write EELAT = 1
2. Write a byte or an aligned word to an EEPROM address
3. Write EEPGM = 1
4. Wait for programming,
5. Write EEPGM = 0
6. Write EELAT = 0
EEPROM
t
PROG
or erase,
t
ERASE
MC68HC912DT128A Rev 2.0
delay time
Program/Erase Operation
Table 20
EEPROM
shows
111