
Memory
Electrically Erasable Programmable ROM (EEPROM)
MC68HC08AS32A — Rev. 1
Data Sheet
MOTOROLA
Memory
51
2.5.2.5 EEPROM Timebase Divider Non-Volatile Register
The 16-bit EEPROM timebase divider non-volatile register consists of two 8-bit
registers: EDIVHNVR and EEDIVLNVR. The contents of these two registers are
respectively loaded into the EEPROM timebase divider registers, EEDIVH and
EEDIVL, after a reset.
These two registers are erased and programmed in the same way as an EEPROM
byte.
These two registers are protected from erase and program operations if the
EEDIVSECD is set to logic 1 in the EEDIVH (see
2.5.2.4 EEPROM Timebase
Divider Register
) or programmed to a logic 1 in the EEDIVHNVR.
NOTE:
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, care should be taken before programming a value into the
EEDIVHNVR.
Address: $FE10
Bit 7
6
5
4
3
2
1
Bit 0
Read:
EEDIVSECD
R
R
R
R
EEDIV10
EEDIV9
EEDIV8
Write:
Reset:
Unaffected by reset; $FF when blank
R
= Reserved
Figure 2-8. EEPROM Divider Non-Volatile Register High
(EEDIVHNVR)
Address: $FE11
Bit 7
6
5
4
3
2
1
Bit 0
Read:
EEDIV7
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
EEDIV1
EEDIV0
Write:
Reset:
Unaffected by reset; $FF when blank
Figure 2-9. EEPROM Divider Non-Volatile Register Low
(EEDIVLNVR)
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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