Freescale Semiconductor, Inc.
EEPROM-1
6.4.3 EEPROM Block Protection
The 512 bytes of EEPROM are divided into four 128-byte blocks. Each
of these blocks can be separately protected by EEBPx bit. Any attempt
to program or erase memory locations within the protected block will not
allow the program/erase voltage to be applied to the array. Table 6-2
shows the address ranges within the blocks.
Table 6-2. EEPROM Array Address Blocks
Block Number (EEBPx)
Address Range
$0800–$087F
$0880–$08FF
$0900–$097F
$0980–$09FF
EEBP0
EEBP1
EEBP2
EEBP3
If EEBPx bit is set, that corresponding address block is protected. These
bits are effective after a reset or a read to EENVR1 register. The block
protect configuration can be modified by erasing/programming the
corresponding bits in the EENVR1 register and then reading the
EENVR1 register.
In redundant mode, EEBP3 and EEBP2 will have no meaning.
6.4.4 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
are 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: Programming the EEPROM in non-redundant mode and programming
the data to its corresponding location before entering redundant mode is
recommended.
Technical Data
MC68HC908AS60 — Rev. 1.0
EEPROM-1
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