mc68hc908jw32 Freescale Semiconductor, Inc, mc68hc908jw32 Datasheet - Page 197

• Manufacturer Part Number: mc68hc908jw32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

16.3.6 Reset Vector Fetch
A reset vector fetch occurs when the vector address appears on the data bus. A reset vector fetch clears
the COP prescaler.
16.3.7 COPD (COP Disable)
The COPD signal reflects the state of the COP disable bit (COPD) in the configuration register (CONFIG).
16.3.8 COPRS (COP Rate Select)
The COPRS signal reflects the state of the COP rate select bit (COPRS) in the configuration register
(CONFIG).
COPRS — COP Rate Select Bit
COPD — COP Disable Bit
16.4 COP Control Register
The COP control register is located at address $FFFF and overlaps the reset vector. Writing any value to
$FFFF clears the COP counter and starts a new timeout period. Reading location $FFFF returns the low
byte of the reset vector.
16.5 Interrupts
The COP does not generate CPU interrupt requests.
Freescale Semiconductor
COPRS selects the COP timeout period. Reset clears COPRS.
COPD disables the COP module.
1 = COP timeout period is (8176) × CGMRCLK cycles
0 = COP timeout period is (262,128) × CGMRCLK cycles
1 = COP module disabled
0 = COP module enabled
Address:
Address:
Reset:
Reset:
Read:
Read:
Write:
Write:
COPRS
$FFFF
$001F
Bit 7
Bit 7
0
Figure 16-2. Configuration Register (CONFIG)
Figure 16-3. COP Control Register (COPCTL)
= Unimplemented
LVISTOP
6
0
6
MC68HC908JW32 Data Sheet, Rev. 5
LVIRSTD
5
0
5
Low byte of reset vector
LVIPWRD
Unaffected by reset
Clear COP counter
4
0
4
3
0
3
SSREC
2
0
2
STOP
1
0
1
COP Control Register
COPD
Bit 0
Bit 0
0
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