MC908AZ60ACFUER Datasheet, PDF (88/414 Pages) Freescale Semiconductor, Inc – To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to:

EEPROM-2 Memory
7.4.3 EEPROM-2 Program/Erase Protection
The EEPROM has a special feature that designates the 16 bytes of addresses from $06F0 to $06FF to
be permanently secured. This program/erase protect option is enabled by programming the EEPRTCT
bit in the EEPROM-2 Nonvolatile Register (EE2NVR) to a logic zero.
Once the EEPRTCT bit is programmed to 0 for the first time:
• Programming and erasing of secured locations $06F0 to $06FF is permanently disabled.
• Secured locations $06F0 to $06FF can be read as normal.
• Programming and erasing of EE2NVR is permanently disabled.
• Bulk and Block Erase operations are disabled for the unprotected locations $0600-$06EF,
$0700-$07FF.
• Single byte program and erase operations are still available for locations $0600-$06EF and
$0700-$07FF for all bytes that are not protected by the EEPROM-2 Block Protect EEBPx bits (see
7.4.4 EEPROM-2 Block Protection and 7.5.2 EEPROM-2 Array Configuration Register)
NOTE
Once armed, the protect option is permanently enabled. As a consequence,
all functions in the EE2NVR will remain in the state they were in
immediately before the security was enabled.
7.4.4 EEPROM-2 Block Protection
The 512 bytes of EEPROM-2 are divided into four 128-byte blocks. Each of these blocks can be protected
from erase/program operations by setting the EEBPx bit in the EE2NVR. Table 7-1 shows the address
ranges for the blocks.
Table 7-1. EEPROM-2 Array Address Blocks
Block Number (EEBPx)
EEBP0
EEBP1
EEBP2
EEBP3
Address Range
$0600–$067F
$0680–$06FF
$0700–$077F
$0780–$07FF
These bits are effective after a reset or a upon read of the EE2NVR register. The block protect
configuration can be modified by erasing/programming the corresponding bits in the EE2NVR register
and then reading the EE2NVR register. Please see 7.5.2 EEPROM-2 Array Configuration Register for
more information.
NOTE
Once EEDIVSECD in the EE2DIVHNVR is programmed to 0 and after a
system reset, the EE2DIV security feature is permanently enabled because
the EEDIVSECD bit in the EE2DIVH is always loaded with 0 thereafter.
Once this security feature is armed, erase and program mode are disabled
for EE2DIVHNVR and EE2DIVLNVR. Modifications to the EE2DIVH and
EE2DIVL registers are also disabled. Therefore, be cautious on
programming a value into the EE2DIVHNVR.
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
88
Freescale Semiconductor