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AR-B1570 User’s Guide
4.3.1 Watchdog Timer Setting
The watchdog timer is a circuit that maybe be used from your program software to detect crash or hang up. The Watchdog timer is automatically disabled after reset. Once you enabled the watchdog timer, your program should trigger the watchdog timer every time before it times out. After you trigger the watchdog timer, the timer will be set to zero and start to count again. If your program fails to trigger the watchdog timer before times out, it will generate a reset pulse to reset the system or trigger the IRQ 9 signal in order to tell your system that the watchdog time is out.
Please refer to the following table in order to properly program Watchdog function
| D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
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1 | Enable | Reset |
| Time period |
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0 | Disable | IRQ 9 |
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Users could test watchdog function under ‘Debug’ program as follows:
C:>debug
!O 214 C8H
Generally, watchdog function would reset system after 8 seconds
!O 214 0H
Disable watchdog function
C:>debug
!O 214 88H
Generally, watchdog function would generate IRQ 9 after 8 seconds
!O 214 0H
Disable watchdog function
4.3.2 Watchdog Timer Trigger
After you enable the watchdog timer, your program must write the same factor as triggering to the watchdog timer at least once during every
C:>debug
!O 214 CFH
Generally, watchdog function would reset system after 15 seconds
!O 214 40H
Disable watchdog function
Trigger success.
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