
Technical Data
MC68HC08RC16 — Rev. 1.0
162
Computer Operating Properly (COP)
MOTOROLA
Computer Operating Properly (COP)
16.2 Introduction
This computer operating properly (COP) module contains a free-running
counter that generates a reset if allowed to overflow. The COP module
helps software recover from runaway code. Clearing the COP counter
periodically prevents a reset.
16.3 Functional Description
The COP counter is a free-running 6-bit counter preceded by a 12-bit
prescaler counter. If not cleared by software, the COP counter overflows
and generates an asynchronous reset after 218 –24 or 213 –24
CGMXCLK cycles, depending on the state of the COP rate select bit
COPRS, in the configuration register (CONFIG). With a 218 –24
CGMXCLK cycle overflow option, a 4.9152-MHz crystal gives a COP
timeout period is 53.3 ms. Writing any value to location $FFFF before an
COPCTL WRITE
CGMXCLK
RESET VECTOR FETCH
RESET CIRCUIT
RESET STATUS REGISTER
INTERNAL RESET SOURCES
CLEAR
STAGES
5–12
12-BIT COP PRESCALER
CLEAR
ALL
STAGES
6-BIT COP COUNTER
COP DISABLE
RESET
COPCTL WRITE
CLEAR
COP MODULE
COPEN (FROM SIM)
COP COUNTER
COP CLOCK
COP
TIMEOUT
STOP INSTRUCTION
COP TIMEOUT PERIOD