Peak 602VL User's Guide
Rev. B0
Dec. 2000
Apendix
Appendix
Appendix A Watch Dog Timer
Watch Dog Timer Working Procedure
The Watch Dog Timer (WDT) is the special hardware device. The WDT function is to monitor the
computer system whether work normally, otherwise, it will have some measures to fix up the system.
It contains a receivable SQW signal from RTC, and could set time and can clear the counter function.
When time is up, WDT can send Reset or NMI signal.
Operator has to write a value into WDT Configuration Register (Write the control value to the Configuration
Port), and clear WDT counter (read the Configuration Port).
Watch Dog Timer character and function
WDT Configuration port
F2h
Default at F2h
Watch Dog Timer
Disabled 1. Default at Disabled
Enabled
2. Enabled for user
′
s programming
WDT Time out active for Reset
Default at Reset
NMI
WDT Active Time
1 sec
2 sec
4 sec
8 sec
16 sec
32 sec
64 sec
Default at 64 sec
