EEPROM-1 Memory
Functional Description
MC68HC908AZ60A — Rev 2.0 Technical Data
MOTOROLA EEPROM-1 Memory 97
B. If more than one valid EEPROM write occurs, the last address and
data will be latched overriding the previous address and data. Once data
is written to the desired address, do not read EEPROM-1 locations other
than the written location. (Reading an EEPROM location returns the
latched data and causes the read address to be latched).
C. The EEPGM bit cannot be set if the EELAT bit is cleared or a non-
valid EEPROM address is latched. This is to ensure proper
programming sequence. Once EEPGM is set, do not read any
EEPROM-1 locations; otherwise, the current program cycle will be
unsuccessful. When EEPGM is set, the on-board programming
sequence will be activated.
D. The delay time for the EEPGM bit to be cleared in AUTO mode is less
than t
EEPGM
. However, on other MCUs, this delay time may be different.
For forward compatibility, software should not make any dependency on
this delay time.
E. 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-1 array.
EEPROM-1 Erasing The programmed state of an EEPROM bit is logic 0. Erasing changes
the state to a logic 1. Only EEPROM-1 bytes in the non-protected blocks
and the EE1NVR register can be erased.
Use the following procedure to erase a byte, block or the entire
EEPROM-1 array:
1. Configure EERAS1 and EERAS0 for byte, block or bulk erase; set
EELAT in EE1CR.
(A)
NOTE: If using the AUTO mode, also set the AUTO bit in Step 1.
2. Byte erase: write any data to the desired address.
(B)
Block erase: write any data to an address within the desired
block.
(B)
Bulk erase: write any data to an address within the array.
(B)
3. Set the EEPGM bit.
(C)
Go to Step 7 if AUTO is set.
