MC68HC08AZ0 Datasheet, PDF (60/444 Pages) Motorola, Inc – Advance Information

EEPROM
Freescale Semiconductor, Inc.
NOTES:
a. EERAS1 and EERAS0 must be cleared for programming,
otherwise the part will be in erase mode
b. Setting the EELAT bit configures the address and data buses
to latch data for programming the array. Only data with a valid
EEPROM address will be latched. If another consecutive valid
EEPROM write occurs, this address and data will override the
previous address and data. Any attempts to read other
EEPROM data will result in the latched data being read. If
EELAT is set, other writes to the EECR will be allowed after a
valid EEPROM write.
c. The EEPGM bit cannot be set if the EELAT bit is cleared and
a non-EEPROM write has occurred. This is to ensure proper
programming sequence. When EEPGM is set, the on-board
charge pump generates the program voltage and applies it to
the user EEPROM array. When the EEPGM bit is cleared, the
program voltage is removed from the array and the internal
charge pump is turned off.
d. Any attempt to clear both EEPGM and EELAT bits with a
single instruction will only clear EEPGM. This is to allow time
for removal of high voltage from the EEPROM array.
e. While these operations must be performed in the order shown,
other unrelated operations may occur between the steps.
EEPROM erasing
MC68HC08AZ0
58
The unprogrammed state is a logic ‘1’. Only the valid EEPROM bytes in
the non-protected blocks and EENVR can be erased.
The following procedure shows how to erase EEPROM:
1. Clear/set EERAS1 and EERAS0 to select byte/block/bulk
erase, and set EELAT in EECR (see Note f.)
2. Write any data to the desired address for byte erase, to any
address in the desired block for block erase, or to any array
address for bulk erase.
3. Set the EEPGM bit. (See Note g.)
4. Wait for a time, t_byte/t_block/t_bulk before erasing the
EEPROM
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4-eeprom
MOTOROLA