MC68HC08AZ16 Datasheet, PDF (48/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

EEPROM
Functional description
EEPROM
redundant mode
To extend the EEPROM data retention, the array can be placed in
redundant mode. In this mode, the first 256 bytes of user EEPROM array
is mapped to the last 256 bytes. Reading, programming and erasing of
the first 256 EEPROM bytes will physically affect two bytes of EEPROM.
Addressing the last 256 bytes will not be recognized. Block protection
still applies but EEBP3 and EEBP2 are meaningless.
NOTE:
It is recommended that the EEPROM be programmed in the
non-redundant mode and the data programmed to its corresponding
location before entering the redundant mode.
EEPROM
configuration
The EEPROM non-volatile register (EENVR) contains configurations
concerning block protection and redundancy. EENVR is physically
located on the bottom of the EEPROM array. The contents are
non-volatile and are not modified by reset. On reset, this special register
loads the EEPROM configuration into a corresponding volatile EEPROM
array configuration register (EEACR). Thereafter, all reads to the
EENVR will result in EEACR being reloaded.
The EEPROM configuration can be changed by programming/erasing
the EENVR like a normal EEPROM byte. The new array configuration
will take effect with a system reset or a read of the EENVR.
MCU configuration
The EEPROM non-volatile register (EENVR) also contains general
purpose bits which can be used to enable/disable functions within the
MCU which, for safety reasons, need to be controlled from non-volatile
memory. On reset, this special register loads the MCU configuration into
the volatile EEPROM array configuration register (EEACR). Thereafter,
all reads to the EENVR will result in EEACR being reloaded.
The MCU configuration can be changed by programming/erasing the
EENVR like a normal EEPROM byte. The new array configuration will
take effect with a system reset or a read of the EENVR.
7-eeprom
MOTOROLA
EEPROM
MC68HC08AZ32
47