I-Bus Hawkfish, User Manual

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Hawkfish User’s Guide
A1-5
2. Select the time-out intervals of WDT (decide the values of D2, D1,
D0 in F2 )
Example: D2~D0 = 0, the time-out interval will be 64 sec.
AND al, 11111000b ; Setting the time-out interval as 64 sec.
3. Enable or Disable the WDT ( decide D3 value in F2)
i.e. D3=0, Disable the WDT
AND al, 11110111b ; Disable the WDT
i.e. D3=1, Enable the WDT
OR al, 00001000b ; Enable the WDT
After completing the above settings, you must output the Control
Registers value to the WDT Configuration Port, before WDT will start
according to the above setting.
MOV dx, F2h ; Setting WDT Configuration Port
OUT dx, al ; Output the Control Register Value
You should build in a mechanism in the program to continue to read the
WDT Configuration Port for clearing the WDT before the time is up.
Appendix 1 - Watch Dog Timer