MC68HC08AS32A Datasheet, PDF (51/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Memory
Electrically Erasable Programmable ROM (EEPROM)
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.
Address: $FE10
Bit 7
6
5
4
3
2
1
Read:
EEDIVSECD R
R
R
R
EEDIV10 EEDIV9
Write:
Reset:
R
= Reserved
Unaffected by reset; $FF when blank
Figure 2-8. EEPROM Divider Non-Volatile Register High
(EEDIVHNVR)
Bit 0
EEDIV8
Address: $FE11
Read:
Write:
Reset:
Bit 7
EEDIV7
6
5
4
3
2
1
EEDIV6 EEDIV5 EEDIV4 EEDIV3 EEDIV2 EEDIV1
Unaffected by reset; $FF when blank
Figure 2-9. EEPROM Divider Non-Volatile Register Low
(EEDIVLNVR)
Bit 0
EEDIV0
NOTE:
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.
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.
MC68HC08AS32A — Rev. 1
MOTOROLA
Memory
For More Information On This Product,
Go to: www.freescale.com
Data Sheet
51