User’s Manual
WIN Enterprises, Inc.
May, 2009
63
Appendix B: LAN Bypass Function (optional)
The power on default for CN20 & CN21 LAN ports is set to normal state.
How to control LAN bypass function by Watchdog Timer
Please follow below steps to set the LAN bypass function control by Watchdog Timer:
1. Setup jumper JP4 to 1-2 shorted
[default] to enable bypass function.
2. Setup jumper JP1 to 2-3 shorted to enable bypass function by Watchdog Timer.
3. Refer to Appendix A to set timer interval value and enable Watchdog Timer.
After setting the timer interval value, the Watchdog Timer begins to count down. You
have to refresh the Watchdog Timer, so that the Watchdog Timer will return to its
initial value; otherwise, your system will set CN20 & CN21
LAN ports to bypass
state after a time-out.
Note: Once the Watchdog Timer time-out you need to restart the system to reset the
timer.
How to control LAN bypass function by GIPO
Please follow below steps to set the LAN bypass function control by GPIO:
1. Setup jumper JP4 to 1-2 shorted
[default] to enable bypass mode.
2. Setup jumper JP1 to 1-2 shorted [default] to enable bypass function by GPIO.
3. Refer to the program code and set CN20 & CN21 LAN ports to Bypass state or
Normal state.
LAN bypass by GPIO
Bypass state:
Normal state:
MOV DX, 050EH
IN AX, DX
AND AH, NOT 00010000b
OUT DX, AX
MOV DX, 050EH
IN AX, DX
OR AH, 00010000b
OUT DX, AX
DOS DEBUG
Bypass state:
Normal state:
- O50E 20 // bypass, 001
0
0000
-O50E 30 // no bypass, 001
1
0000
