MC68HC908GR16 Datasheet, PDF (85/310 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Data Sheet — MC68HC908GR16
Section 6. Computer Operating Properly (COP) Module
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
CONFIG register.
6.2 Functional Description
Figure 6-1 shows the structure of the COP module.
CGMXCLK
12-BIT COP PRESCALER
RESET CIRCUIT
RESET STATUS REGISTER
STOP INSTRUCTION
INTERNAL RESET SOURCES
RESET VECTOR FETCH
COPCTL WRITE
COPEN (FROM SIM)
COP DISABLE
(FROM CONFIG)
RESET
COPCTL WRITE
COP RATE SEL
(FROM CONFIG)
COP CLOCK
COP MODULE
6-BIT COP COUNTER
CLEAR
COP COUNTER
Figure 6-1. COP Block Diagram
MC68HC908GR16 — Rev. 1.0
MOTOROLA
Computer Operating Properly (COP) Module
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Data Sheet
85