Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
326 Computer Operating Properly (COP) MOTOROLA
Computer Operating Properly (COP)
16.4.4 Internal Reset
An internal reset clears the SIM counter and the COP counter.
16.4.5 Reset Vector Fetch
A reset vector fetch occurs when the vector address appears on the data
bus. A reset vector fetch clears the SIM counter.
16.4.6 COPD (COP Disable)
The COPD signal reflects the state of the COP di sable bit (COPD) in the
configuration register (CONFIG). See Section 5. Configuration
Register (CONFIG).
16.5 COP Control Register
The COP control register is located at address $FFFF and overlap s 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.
16.6 Interrupts
The COP does not generate CPU interrupt requests.
Address: $FFFF
Bit 7654321Bit 0
Read: Low byte of reset vector
Write: Clear COP counter
Reset: Unaffected by reset
Figure 16-3. COP Control Register (COPCTL)