Advantech ASMB-781, User Manual

Page: 72 / 92

ASMB-781 User Manual 62
The ASMB-781’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 pro-
gram it.
A.1 Watchdog timer overview
The watchdog timer is built in to the super I/O controller NCT6776F. 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.2 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 write an address value into
address port 2E (hex), and then write/read data to/from the assigned register through
data port 2F (hex).