mc68hc08qa24 Freescale Semiconductor, Inc, mc68hc08qa24 Datasheet - Page 78

• Manufacturer Part Number: mc68hc08qa24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Electrically Erasable Programmable Read-Only Memory (EEPROM)
6.4.3 EEPROM Block Protection
6.4.4 EEPROM Redundant Mode
6.4.5 EEPROM Configuration
Technical Data
76
NOTE:
Electrically Erasable Programmable Read-Only Memory (EEPROM)
The 512 bytes of EEPROM are divided into four 128-byte blocks. Each
of these blocks can be protected separately by the 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
If the EEBPx bit is set, that corresponding address block is protected.
These bits are effective after a reset or a read to the EENVR. The block
protect configuration can be modified by erasing/programming the
corresponding bits in the EENVR register and then reading the EENVR
register.
In redundant mode, EEBP3 and EEBP2 will have no meaning.
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 ($0800–$08FF) 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.
Before entering redundant mode, program the EEPROM in
non-redundant mode.
The EENVR contains configurations concerning block protection and
redundancy. EENVR is physically located on the bottom of the EEPROM
shows the address ranges within the blocks.
Block Number (EEBPx)
Table 6-2. EEPROM Array Address Blocks
EEBP0
EEBP1
EEBP2
EEBP3
Address Range
$0800–$087F
$0880–$08FF
$0900–$097F
$0980–$09FF
Freescale Semicon-
MC68HC08QA24