s908az32ag2cfue Freescale Semiconductor, Inc, s908az32ag2cfue Datasheet - Page 53

• Manufacturer Part Number: s908az32ag2cfue
• Description: M68hc08 Microcontrollers 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

5.4.3 EEPROM Program/Erase Protection
The EEPROM has a special feature that designates the 16 bytes of addresses from $08F0 to $08FF to
be permanently secured. This program/erase protect option is enabled by programming the EEPRTCT
bit in the EEPROM Nonvolatile Register (EENVR) to a logic zero.
Once the EEPRTCT bit is programmed to 0 for the first time:
5.4.4 EEPROM Block Protection
The 512 bytes of EEPROM 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 EENVR.
ranges for the blocks.
These bits are effective after a reset or a upon read of the EENVR register. The block protect configuration
can be modified by erasing/programming the corresponding bits in the EENVR register and then reading
the EENVR register. Please see
Freescale Semiconductor
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Programming and erasing of secured locations $08F0 to $08FF is permanently disabled.
Secured locations $08F0 to $08FF can be read as normal.
Programming and erasing of EENVR is permanently disabled.
Bulk and Block Erase operations are disabled for the unprotected locations $0800-$08EF,
$0900-$09FF.
Single byte program and erase operations are still available for locations $0800-$08EF and
$0900-$09FF for all bytes that are not protected by the EEPROM Block Protect EEBPx bits (see
5.4.4 EEPROM Block Protection
Once armed, the protect option is permanently enabled. As a consequence,
all functions in the EENVR will remain in the state they were in immediately
before the security was enabled.
Once EEDIVSECD in the EEDIVHNVR is programmed to 0 and after a
system reset, the EEDIV security feature is permanently enabled because
the EEDIVSECD bit in the EEDIVH is always loaded with 0 thereafter. Once
this security feature is armed, erase and program mode are disabled for
EEDIVHNVR and EEDIVLNVR. Modifications to the EEDIVH and EEDIVL
registers are also disabled. Therefore, be cautious on programming a value
into the EEDIVHNVR.
Block Number (EEBPx)
Table 5-1. EEPROM Array Address Blocks
5.5.2 EEPROM Array Configuration Register
EEBP0
EEBP1
EEBP2
EEBP3
MC68HC908AZ32A Data Sheet, Rev. 2
and
5.5.2 EEPROM Array Configuration
NOTE
NOTE
Address Range
$0800–$087F
$0880–$08FF
$0900–$097F
$0980–$09FF
Table 5-1
for more information.
Register)
shows the address
Functional Description
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