MC68HCP11 Datasheet, PDF (17/45 Pages) Motorola, Inc – 8-Bit Microcontroller

4 Electrically Erasable Programmable Read-Only Memory (EEPROM)
The 512 bytes of EEPROM in the MC68HC11A8 are located at $B600 through $B7FF. The EEON bit
in CONFIG controls the presence or absence of the EEPROM in the memory map. When EEON = 1
(erased state), the EEPROM is enabled. When EEON = 0, the EEPROM is disabled and out of the
memory map. EEON is reset to the value last programmed into CONFIG. An on-chip charge pump de-
velops the high voltage required for programming and erasing. When the E clock is less than 1 MHz,
select an internal clock. This drives the EEPROM charge pump by writing a one to the CSEL bit in the
OPTION register.
The PPROG register controls the programming and erasing of the EEPROM. To erase the EEPROM,
complete the following steps using the PPROG register:
1. Write to PPROG with the ERASE, EELAT, and appropriate BYTE and ROW bits set.
2. Write to the appropriate EEPROM address with any data. Row erase only requires a write to
any location in the row. Bulk erase is accomplished by writing to any location in the array.
3. Write to PPROG with ERASE, EELAT, EEPGM, and the appropriate BYTE and ROW bits set.
4. Delay for 10 ms or more, as appropriate.
5. Clear the EEPGM bit in PPROG to turn off the high voltage.
6. Clear the PPROG register to reconfigure the EEPROM address and data buses for normal op-
eration.
To program the EEPROM, complete the following steps using the PPROG register:
1. Write to PPROG with the EELAT bit set.
2. Write data to the desired address.
3. Write to PPROG with the EELAT and EEPGM bits set.
4. Delay for 10 ms or more, as appropriate.
5. Clear the EEPGM bit in PPROG to turn off the high voltage.
6. Clear the PPROG register to reconfigure the EEPROM address and data buses for normal op-
eration.
PPROG — EEPROM Programming Control
Bit 7
6
5
4
ODD EVEN
0
BYTE
RESET:
0
0
0
0
3
ROW
0
$103B
2
ERASE
0
1
EELAT
0
Bit 0
EEPGM
0
ODD — Program Odd Rows in Half of EEPROM (TEST)
EVEN — Program Even Rows in Half of EEPROM (TEST)
BYTE — Byte/Other EEPROM Erase Mode
The BYTE bit overrides the ROW bit.
0 = Row or bulk erase mode is used
1 = Erase only one byte of EEPROM
ROW — Row/All EEPROM Erase Mode
The ROW bit is only valid when BYTE = 0.
0 = All 512 bytes of EEPROM are erased
1 = Erase only one 16-byte row of EEPROM
BYTE
0
0
1
1
ROW
0
1
0
1
Action
Bulk Erase (All 512 Bytes)
Row Erase (16 Bytes)
Byte Erase
Byte Erase
MC68HC11A8
MC68HC11A8TS/D
MOTOROLA
17