Datasheet

Computer Operating Properly (COP)
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
164 Freescale Semiconductor
Figure 15-1. COP Block Diagram
15.3.1 CGMXCLK
CGMXCLK is the crystal oscillator output signal. CGMXCLK frequency is equal to the crystal frequency.
15.3.2 STOP Instruction
The STOP instruction clears the COP prescaler.
15.3.3 COPCTL Write
Writing any value to the COP control register (COPCTL) (see 15.4 COP Control Register), clears the COP
counter and clears stages 12 through 4 of the COP prescaler. Reading the COP control register returns
the reset vector.
15.3.4 Power-On Reset
The power-on reset (POR) circuit clears the COP prescaler 4096 CGMXCLK cycles after power-up.
15.3.5 Internal Reset
An internal reset clears the COP prescaler and the COP counter.
COPCTL WRITE
CGMXCLK
RESET VECTOR FETCH
RESET
RESET STATUS
INTERNAL RESET SOURCES
STOP INSTRUCTION
CLEAR STAGES 4–12
CLEAR ALL STAGES
6-BIT COP COUNTER
COPD FROM CONFIG-1
RESET
COPCTL WRITE
CLEAR COP
COUNTER
COPL FROM CONFIG-1
12-BIT COP PRESCALER
REGISTER