Datasheet

MC68HC908QY/QT Family Data Sheet, Rev. 6
Freescale Semiconductor 57
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
COPCTL WRITE
BUSCLKX4
RESET CIRCUIT
RESET STATUS REGISTER
INTERNAL RESET SOURCES
12-BIT SIM COUNTER
CLEAR ALL STAGES
6-BIT COP COUNTER
COP DISABLE (COPD FROM CONFIG1)
RESET
COPCTL WRITE
CLEAR
COPEN (FROM SIM)
COP COUNTER
COP CLOCK
COP TIMEOUT
STOP INSTRUCTION
COP RATE SELECT
(COPRS FROM CONFIG1)
CLEAR STAGES 5–12