MC68HC705 MOTOROLA [Motorola, Inc], MC68HC705 Datasheet - Page 61

• Manufacturer Part Number: MC68HC705
• Description: HCMOS Microcontroller Unit
• Manufacturer: MOTOROLA [Motorola, Inc]

5.3.3.1 Programmable COP Watchdog Reset
MC68HC705C8A — Rev. 2.0
MOTOROLA
INTERNAL
COPRST
CLOCK
(f
OP
)
PROGRAMMABLE COP WATCHDOG (MC68HC705C8 TYPE)
4
Figure 5-1. Programmable COP Watchdog Diagram
4
One COP has four programmable timeout periods and the other has a
fixed non-programmable timeout period.
A timeout of the 18-stage ripple counter in the programmable COP
watchdog generates a reset.
programmable COP watchdog. Two registers control and monitor
operation of the programmable COP watchdog:
To clear the programmable COP watchdog and begin a new timeout
period, write these values to the COP reset register (COPRST).
See
The $55 write must precede the $AA write. Instructions may be executed
between the write operations provided that the COP watchdog does not
time out before the second write.
2
1. $55
2. $AA
•
•
2
Figure
2
COP reset register (COPRST), $001D
COP control register (COPCR), $001E
2
2
2
5-2.
2
2
2
2
2
2
Resets
2
2
2
Figure 5-1
2
2
2
13
2
CM0
CM1
2
2
2
2
2
15
17
19
21
is a diagram of the
2
2
2
PCOPE
Reset Sources
Technical Data
RESET
Resets
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