MC68HC812A4 Datasheet, PDF (118/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

EEPROM
If BYTE = 1 and test mode is not enabled, only the location specified by
the address written to the programming latches is erased. The operation
is a byte or an aligned word erase depending on the size of written data.
ERASE — Erase Control Bit
1 = EEPROM configuration for erasure
0 = EEPROM configuration for programming
Write anytime, if EEPGM = 0
This bit configures the EEPROM for erasure or programming.
EELAT — EEPROM Latch Control Bit
1 = EEPROM address and data bus latches set up for
programming or erasing
0 = EEPROM set up for normal reads
Write anytime, if EEPGM = 0
NOTE:
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.
BYTE, ROW, ERASE, and EELAT bits can be written simultaneously or
in any sequence.
EEPGM — Program and Erase Enable Bit
1 = Applies program/erase voltage to EEPROM
0 = Disables program/erase voltage to EEPROM
The EEPGM bit can be set only after EELAT has been set. When
EELAT and EEPGM are set simultaneously, EEPGM remains clear
but EELAT is set.
The BULKP, BYTE, ROW, ERASE, and EELAT bits cannot be
changed when EEPGM is set. To complete 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.
MC68HC812A4 — Rev. 3.0
118
EEPROM
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