mc68hc912bc32 Freescale Semiconductor, Inc, mc68hc912bc32 Datasheet - Page 97

• Manufacturer Part Number: mc68hc912bc32
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

If BYTE = 1 and test mode is not enabled, only the location specified by the address written to the
programming latches will be erased. The operation will be a byte or an aligned word erase depending on
the size of written data.
ERASE — Erase Control Bit
EELAT — EEPROM Latch Control Bit
EEPGM — Program and Erase Enable Bit
The BULKP, BYTE, ROW, ERASE, and EELAT bits cannot be changed when EEPGM is set. To complete
a program or erase, a write to clear EEPGM and EELAT bits is 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 this sequence:
To program/erase more bytes or words without intermediate EEPROM reads, only write EEPGM = 0 in
step 5, leaving EELAT = 1, and jump to step 2.
Freescale Semiconductor
1. Write BYTE, ROW, and ERASE to the desired value;
2. Write a byte or an aligned word to an EEPROM address.
3. Write EEPGM = 1.
4. Wait for programming (
5. Write EEPGM = 0 and EELAT = 0.
Read anytime. Write anytime if EEPGM = 0.
Configures the EEPROM for erasure or programming.
When test mode is not enabled and unless BULKP is set, erasure is by byte, aligned word, row, or bulk.
Read anytime. Write anytime if EEPGM = 0.
BYTE, ROW, ERASE, and EELAT bits can be written simultaneously or in any sequence.
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.
0 = EEPROM configuration for programming or reading
1 = EEPROM configuration for erasure
0 = EEPROM set up for normal reads
1 = EEPROM address and data bus latches set up for programming or erasing
0 = Disables program/erase voltage to EEPROM
1 = Applies program/erase voltage to EEPROM
write EELAT = 1.
When EELAT is set, the entire EEPROM is unavailable for reads.
Therefore, no program residing in the EEPROM can be executed while
attempting to program unused 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.
t
PROG
) or erase (
M68HC12B Family Data Sheet, Rev. 9.1
t
Erase
NOTE
) delay time.
EEPROM Control Registers
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