Datasheet

MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor 61
Chapter 6
Computer Operating Properly (COP)
6.1 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 recover from runaway code. Prevent a COP reset
by clearing the COP counter periodically. The COP module can be disabled through the COPD bit in the
configuration 1 (CONFIG1) register.
6.2 Functional Description
Figure 6-1. COP Block Diagram
1. See Chapter 14 System Integration Module (SIM) for more details.
COPCTL WRITE
BUSCLKX4
STOP INSTRUCTION
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