System Installation
ROBO-8920VG2 User’s Manual
3-5
3.4
Clear CMOS Operation
The following table indicates how to enable/disable CMOS Clear Function hardware
circuit by putting jumpers at proper position.
Normal Clear
JP1
Function
1-2 Short
Normal Operation
Ì
2-3 Short
Clear CMOS contents
3.5
WDT Function
The working algorithm of the WDT function can be simply described as a counting
process. The Time-Out Interval can be set through software programming. The
availability of the time-out interval settings by software or hardware varies from
boards to boards.
ROBO-8920VG2 allows users control WDT through dynamic software
programming. The watchdog timer (WDT) is integrated into E6300ESB I/O
Controller Hub ( ICH ) and provides a resolution that ranges from 1 msecond to 10
minutes. The WDT provides a two-stage timer implementation : the first stage can be
used to generate an IRQ,SMI or SCI interrupt after the programmed time interval
has interval has expired ; the second stage can be used to generate a hard system
reset.
The WDT uses a 35-bit down-counter, which is loaded with the value from the first
preload register. The timer is then enabled and starts its down counting, which is the
first stage. When the host fails to reload the WDT before the 35-bit down-counter
reaches zero, the WDT generates an internal interrupt. After the interrupt is
generated, the WDT loads the value from the second preload register into 35-bit
down-counter and starts counting down. The WDT is now in the second stage. If the
host fails to reload the WDT before the second stage times out, a system RESET is
generated.
E6300ESB pin M24 ( WDTOUT) is active low, the watchdog timer is a hardware
timer which resets the SHB if the timer is not refreshed by software periodically. The
timer is typically used to restart a system in which an application becomes hung on
an external event. When the application is hung, it no longer refreshes the timer. The
watchdog timer then times out and resets the SHB. For more information about
WDT, please refer to Intel E6300ESB data sheet. http://www.intel.com
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