System Installation
3303788
User’s Manual
3-
6
3-4-
3
On-board LED Indicator
The
3303788
provides three LED indicators to show LAN interface status.
These messages will give you a guide for troubleshooting.
LED1 (top) (LAN speed LED)
ON : indicates 100Mbps activity
OFF : indicates 10Mbps activity
LED2 (center) (LAN active LED)
ON : indicates Tx/Rx activity
OFF : no activity
LED3 (bottom) (LAN Link Integrity LED)
ON : indicates link is good in either 10 or 100 Mbps
OFF : link is bad
3-5 Watch Dog Timer Programming
There are two manners to activate the Watch-Dog Timer (WDT) function. One
is to utilize hardware jumper setting and programmed by software command.
After this feature is enabled, a system reset will be generated unless a
application triggers the timer periodically within time-out period. This allows
the system to restart in an orderly way in case of any abnormal condition is
found. Another one is to program super I/O W83977ATF chip to start WDT
time-out counting. It is recommended to use first approach. The second choice
is comparatively difficult and complicated. In addition, you can also connect
WDT output to NMI input by setting JP6 jumper to generate NMI event to
support special interrupt service routine.
An optional two-port WDT is provided on
3303788
. This WDT comes with
8 possible ranges of time intervals from 500 ms to 64 sec., which can be
adjusted 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 1second, the WDT
trigger command must be issued within 700ms at least.
The below example gives you a reference algorithm for WDT programming via
I/O port 0533H and 0033H in your application program :
