MC68HC908JW32_09 Datasheet, PDF (197/232 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Chapter 16
Computer Operating Properly (COP)
16.1 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
CONFIG register.
16.2 Functional Description
Figure 16-1 shows the structure of the COP module.
CGMRCLK
SIM
12-BIT SIM COUNTER
SIM RESET CIRCUIT
RESET STATUS REGISTER
INTERNAL RESET SOURCES⁽¹⁾
RESET VECTOR FETCH
COPCTL WRITE
COPEN (FROM SIM)
COPD (FROM CONFIG)
RESET
COPCTL WRITE
COP RATE SEL
(COPRS FROM CONFIG)
COP CLOCK
COP MODULE
6-BIT COP COUNTER
CLEAR
COP COUNTER
Figure 16-1. COP Block Diagram
MC68HC908JW32 Data Sheet, Rev. 6
Freescale Semiconductor
197