MC68HC08AZ32A Datasheet, PDF (78/312 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Computer Operating Properly (COP) Module
CGMXCLK
SIM
12-BIT SIM COUNTER
STOP INSTRUCTION
INTERNAL RESET SOURCES⁽¹⁾
RESET VECTOR FETCH
COPCTL WRITE
COPEN (FROM SIM)
COPD (FROM MORA)
RESET
COPCTL WRITE
COPS
COP MODULE
6-BIT COP COUNTER
CLEAR
COP COUNTER
SIM RESET CIRCUIT
SIM RESET STATUS REGISTER
1. See 15.3.2 Active Resets From Internal Sources.
Figure 5-1. COP Block Diagram
5.3 I/O Signals
The following paragraphs describe the signals shown in Figure 5-1.
5.3.1 CGMXCLK
CGMXCLK is the crystal oscillator output signal. The CGMXCLK frequency is equal to the crystal
frequency.
5.3.2 STOP Instruction
The STOP instruction clears the COP prescaler.
5.3.3 COPCTL Write
Writing any value to the COP control register (COPCTL) (5.4 COP Control Register (COPCTL)), clears
the COP counter and clears stages 12 through 4 of the COP prescaler. Reading the COP control register
returns the reset vector.
MC68HC08AZ32A Data Sheet, Rev. 2
78
Freescale Semiconductor