MC68HC912BL16 Datasheet, PDF (53/128 Pages) Freescale Semiconductor, Inc – 16-Bit Microcontroller

Freescale Semiconductor, Inc.
gram residing in the EEPROM can be executed while attempting to program un-
used EEPROM space. Care should be taken that no references to the EEPROM
are used while programming. Interrupts should be turned off if the vectors are in
the EEPROM. Timing and any serial communications must be done with polling
during the programming process.
BYTE, ROW, ERASE and EELAT bits can be written simultaneously or in any sequence.
EEPGM — Program and Erase Enable
0 = Disables program/erase voltage to EEPROM.
1 = Applies program/erase voltage to EEPROM.
The EEPGM bit can be set only after EELAT has been set. When an attempt is made to set EELAT and
EEPGM simultaneously, EEPGM remains clear but EELAT is set.
The BULKP, BYTE, ROW, ERASE and EELAT bits cannot be changed when EEPGM is set. To com-
plete a program or erase, two successive writes to clear EEPGM and EELAT bits are required before
reading the programmed data. A write to an EEPROM location has no effect when EEPGM is set.
Latched address and data cannot be modified during program or erase.
A program or erase operation should follow the sequence below:
1. Write BYTE, ROW and ERASE to the 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 (t_PROG) or erase (t_ERASE) delay time
5. Write EEPGM = 0
6. Write EELAT = 0
It is possible to program/erase more bytes or words without intermediate EEPROM reads, by jumping
from step 5 to step 2.
MC68HC912BL16TS/D
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