mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 63

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Interrupts
6.3.7 COPRS (COP Rate Select)
The COPRS signal reflects the state of the COP rate select bit (COPRS) in the configuration register 1
(CONFIG1). See
Chapter 5 Configuration Register
(CONFIG).
6.4 Interrupts
The COP does not generate CPU interrupt requests.
6.5 Monitor Mode
The COP is disabled in monitor mode when V
is present on the IRQ pin.
TST
6.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
6.6.1 Wait Mode
The COP continues to operate during wait mode. To prevent a COP reset during wait mode, periodically
clear the COP counter.
6.6.2 Stop Mode
Stop mode turns off the BUSCLKX4 input to the COP and clears the SIM counter. Service the COP
immediately before entering or after exiting stop mode to ensure a full COP timeout period after entering
or exiting stop mode.
6.7 COP Module During Break Mode
The COP is disabled during a break interrupt with monitor mode when BDCOP bit is set in break auxiliary
register (BRKAR).
6.8 Register
The COP control register (COPCTL) 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.
Bit 7
6
5
4
3
2
1
Bit 0
Read:
LOW BYTE OF RESET VECTOR
Write:
CLEAR COP COUNTER
Reset:
Unaffected by reset
Figure 6-2. COP Control Register (COPCTL)
MC68HC908QB8 Data Sheet, Rev. 2
Freescale Semiconductor
63