MC68HC08AZ16 Datasheet, PDF (46/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

EEPROM
Functional description
NOTES:
F. Setting the EELAT bit configures the address and data buses
to latch data for erasing the array. Only valid EEPROM
addresses with its data will be latched. If another consecutive
valid EEPROM write occurs, this address and data will
override the previous address and data. In block erase mode,
any EEPROM address in the block may be used in step 2. All
locations within this block will be erased. In bulk erase mode,
any EEPROM address may be used to erase the whole
EEPROM. EENVR is not affected with block or bulk erase.
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.
G. The EEPGM bit cannot be set if the EELAT bit is cleared and
a non-EEPROM write has occurred. This is to ensure proper
erasing sequence. Once EEPGM is set, the type of erase
mode cannot be modified. If EEPGM is set, the on-board
charge pump generates the erase voltage and applies it to the
user EEPROM array. When the EEPGM bit is cleared, the
erase voltage is removed from the array and the internal
charge pump is turned off.
H. 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.
In general, all bits should be erased before being programmed.
However, if program/erase cycling is of concern, minimize bit cycling in
each EEPROM byte. If any bit in a byte requires to be changed from a
’0’ to a ‘1’, the byte needs be erased before programming. Table 1
summarizes the conditions for erasing before programming.
5-eeprom
MOTOROLA
EEPROM
MC68HC08AZ32
45