MC68HC08AZ0 Datasheet, PDF (164/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
Computer Operating Properly Module (COP)
I/O Signals
The following paragraphs describe the signals shown in Figure 1.
CGMXCLK
CGMXCLK is the crystal oscillator output signal. The CGMXCLK
frequency is equal to the crystal frequency.
STOP instruction
The STOP instruction clears the COP prescaler.
COPCTL write
Writing any value to the COP control register (COPCTL) (see COP
Control register (COPCTL) on page 163), clears the COP counter and
clears bits 12 – 4 of the SIM counter. Reading the COP control register
returns the reset vector.
Power-on reset
The power-on reset (POR) circuit in the SIM clears the SIM counter 4096
CGMXCLK cycles after power-up.
Internal reset
An internal reset clears the COP prescaler and the COP counter.
Reset vector fetch A reset vector fetch occurs when the vector address appears on the data
bus. A reset vector fetch clears the COP prescaler.
COPD (COP
disable)
The COPD signal reflects the state of the COP disable bit (COPD) in the
mask option register (MORA). See Mask Options on page 135
MC68HC08AZ0
162
Computer Operating Properly Module (COP)
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