Datasheet

MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
Freescale Semiconductor 51
Chapter 5
Computer Operating Properly Module (COP)
5.1 Introduction
The computer operating properly (COP) module contains a free-running counter that generates a reset if
allowed to overflow. The COP module helps software to recover from a runaway code. Periodically
clearing the COP counter will prevent a COP reset from occurring. The COP module can be disabled
through the COPD bit in the configuration (CONFIG) register.
5.2 Block Diagram
Figure 5-1. COP Block Diagram
COPCTL WRITE
BUSCLKX4
RESET VECTOR FETCH
SIM RESET CIRCUIT
RESET STATUS REGISTER
INTERNAL RESET SOURCES
(1)
SIM MODULE
CLEAR STAGES 5–12
12-BIT SIM COUNTER
CLEAR ALL STAGES
COPD (FROM CONFIG1)
RESET
COPCTL WRITE
CLEAR
COP MODULE
COPEN (FROM SIM)
COP CLOCK
COP TIMEOUT
COP RATE SELECT
(COPRS FROM CONFIG1)
6-BIT COP COUNTER
COP COUNTER