Appendix A Programming The Watchdog; Programming The Watchdog Timer; Watchdog Timer Working Procedure; Table A.1:Installing The Heatsink - Advantech PCA-6289 User Manual

Appendix A Programming the watchdog

A.1 Programming the Watchdog Timer
The PCA-6289's watchdog timer can be used to monitor system software
operation and take corrective action if the software fails to function after
the programmed period. This section describes the operation of the
watchdog timer and how to program it.
A.1.1 Watchdog Timer Working Procedure
Watchdog Timer (WDT) is a special hardware device that monitors the
computer system during normal operation. WDT has a clock circuit that
times down from a set number to zero. If a monitored item occurs before
the timer reaches zero, WDT resets and counts down again. If for some
reason the monitored item doesn't occur before
the timer reaches zero, WDT performs an action, such as a diagnostic
operation (rebooting the computer). You must enter timer values into
WDT Configuration Register (Write the control value to the Configura-
tion Port), and clear WDT counter (read the Configuration Port).
Table A.1: Installing the heatsink
WDT Configuration port
Watch Dog Timer
WDT Active Time
A.1.2 Watchdog Timer Control Register
The Watchdog Timer Control Register controls the WDT working mode.
Write the value to the WDT Configuration Port. The following table
describes the Control Register bit definition:
PCA-6289 User's Manual
F2
Disabled
Enabled
1 sec
2 sec
4 sec
8 sec
16 sec
32 sec
64 sec
128 sec
46
Default at F2
Default at disabled
Enabled for user's
programming
Default at 64 sec