Advantech PCA-6194, User Manual

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PCA-6194 User Manual 90
Appendix A Watchdog Timer
A.1 Programming the Watchdog Timer
The PCA-6194's watchdog timer can be used to monitor system software
operation and take corrective action if the software fails to function
within the programmed period. This section describes the operation of the
watchdog timer and how to program it.
A.1.1 Watchdog timer overview
The watchdog timer is built in to the super I/O controller W83627HG. It
provides the following functions for user programming:
• Can be enabled and disabled by user's program
• Timer can be set from 1 to 255 seconds or 1 to 255 minutes
• Generates an interrupt or resets signal if the software fails to reset the
timer before time-out
A.1.2 Jumper selection
The JWDT1 jumper is used to select reset in the event the watchdog timer
is tripped. See Chapter 1 for detailed jumper settings.
A.1.3 Programming the Watchdog Timer
The I/O port address of the watchdog timer is 2E(hex) and 2F(hex).
2E (hex) is the address port. 2F(hex) is the data port. You must first
assign the address of register by writing an address value into address
port 2E (hex), then write/read data to/from the assigned register through
data port 2F (hex).