mc68hc705k1 Freescale Semiconductor, Inc, mc68hc705k1 Datasheet - Page 80

• Manufacturer Part Number: mc68hc705k1
• Description: Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Multifunction Timer
8.5 COP Watchdog
Technical Data
NOTE:
Address:
Four counter stages at the end of the timer make up the mask-optional
computer operating properly (COP) watchdog. The COP watchdog is a
software error detection system that automatically times out and resets
the MCU if not cleared periodically by a program sequence. Writing a
logic 0 to bit 0 of the COP register clears the COP watchdog and
prevents a COP reset.
COPC — COP Clear Bit
If the voltage on the IRQ/V
turns off and remains off until the IRQ/V
Reset:
Read:
Write:
This write-only bit resets the COP watchdog. Reading address $03F0
returns the read-only memory (ROM) data at that address.
The COP watchdog is active in the run, wait, and halt modes of
operation if the COPEN bit in the mask option register is set.
The STOP instruction disables the COP watchdog by clearing the
counter and turning off its clock source. In applications that depend
on the COP watchdog, the STOP instruction can be disabled by
programming the SWAIT bit to a logic 1 in the mask option register. In
applications that have wait cycles longer than the COP timeout
period, the COP watchdog can be disabled by not programming the
COPEN bit to a logic 1 in the mask option register.
Freescale Semiconductor, Inc.
For More Information On This Product,
$03F0
Bit 7
U
Go to: www.freescale.com
= Unimplemented
Multifunction Timer
Figure 8-4. COP Register (COPR)
U
6
U
5
PP
pin exceeds 2
U = Unaffected
U
4
PP
U
3
voltage falls below 2
V
DD
MC68HC705K1 — Rev. 2.0
, the COP watchdog
U
2
U
1
COPC
Bit 0
V
0
DD
.