Appendix B - Watchdog Timer Programming Guide - ADLINK Technology cPCI-6810 User Manual

Appendix B - WatchDog Timer Programming Guide

The Watchdog Timer (WDT) can monitor the system's status.
Once a value is given to the WDT, the timer will begin to count
down. If the system becomes idle or hangs, the system will reboot
itself when the timer times out.
The Watch Dog timer includes an 8-bit timer clocked by a 1-minute
internal clock that is derived from the battery-backed 32.768KHz
crystal clock generator. The timer is loaded with the WATCHDOG
Time-Out data value written in the WDTO register and counts
down to zero. This 8-bit data enables time-out values between 1
and 255 minutes to be programmed (00h is an invalid data value).
The following events can trigger the WATCHDOG by reloading the
timer:
Keyboard interrupt
Mouse interrupt
Serial Port 1 interrupt
Serial Port 2 interrupt
Software writing to control register
All control registers are accessed through the following I/O ports.
Appendix
I/O mapped Port
Index port
2EH
Data Port
2FH
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