System Installation
ROBO-638 User’s Manual
3-7
This WDT comes with 8 possible ranges of time intervals from 500 ms to 64
seconds, which is adjustable by setting jumper positions. It could be enabled
and programmed by reading I/O port 0533H or 0543H to issue trigger
continuously, and disabled by reading I/O port 0033H or 0343H. A tolerance of
30% timer limit must be considered. For instance, if the time-out interval is set
to 1 second, the WDT trigger command must be issued within 700ms at least.
The example below gives you a sample algorithm for WDT programming via
I/O port 0533H and 0033H in your application program :
Enable WDT
MOV
DX,
0533H
IN
AL, DX
Re-trigger WDT
MOV
DX,
0533H
IN
AL,
DX
Disable WDT
MOV
DX,
0033H
IN
AL,
DX
NOTE : Please directly contact your technical specialist to get WDT
programming information on super I/O chip for long time-out interval
support from 0.5 minutes to 254.5 minutes.
