Nexcom PEAK 7220VL2G User Manual page 62

i.e. D3=1, Enables WDT
OR al, 00001000b ; Enable the WDT
After finishing the above settings, you must output the Control Register's value to
WDT Configuration Port. Then WDT will start according to the above settings.
MOV dx, F2h ; Setting WDT Configuration Port
OUT dx, al ; Output the Control Register Value
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