Chapter 3 BIOS Configuration
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PISA-E1 User’s Manual
Watchdog Timer Configuration
The function of the watchdog timer is to reset the system automatically and is
defined at I/O port 0443H. To enable the watchdog timer and allow the system to
reset, read I/O port 0443H. To disable the timer, read I/O port 043H for the
system to stop the watchdog function. The timer has a tolerance of 20% for its
intervals.
The following describes how the timer should be programmed.
Enabling Watchdog
MOV DX,
0443H
IN
DX, AX
Disabling Watchdog
MOV DX, 043H
OUT
DX, AX
