Freescale Semiconductor MC68HC908MR32 - Manual (Page 75)

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor 75
Chapter 6
Computer Operating Properly (COP)
6.1 Introduction
This section describes the computer operating properly module, a free-running counter that generates a
reset if allowed to overflow. The computer operating properly (COP) module helps software recover from
runaway code. Prevent a COP reset by periodically clearing the COP counter.
6.2 Functional Description
Figure 6-1 shows the structure of the COP module. A summary of the input/output (I/O) register is shown
in Figure 6-2 .
Figure 6-1. COP Block Diagram
COPCTL WRITE
CGMXCLK
RESET VECTOR FETCH
SIM RESET CIRCUIT
SIM RESET STATUS REGISTER
INTERNAL RESET SOURCES(1)
SIM
CLEAR BITS 12–4
13-BIT SIM COUNTER
CL
EAR A
LL
BIT
S
6-BIT COP COUNTER
COPD (FROM CONFIG)
RESET
COPCTL WRITE
CLEAR
COP MODULE
COP COUNTER
Note 1. See 14.3.2 Active Resets from Internal Sources .