System Installation
PEB-2738I User’s Manual
3-4
3.5 Clear
CMOS
Operation
The following table indicates how to enable/disable Clear CMOS Function hardware
circuit by putting jumpers at proper position.
JP7 : CMOS Reset
JP8
Function
1-2 Normal
Operation
Ì
2-3
Clear CMOS Contents
To correctly operate CMOS Clear function, users must turn off the system, move JP8
jumper to short pin 2 and 3. Move the JP8 back to 1-2 position (Normal Operation)
and start the system. System will then produce a “CMOS Check Sum Error” message
and hold up. Users may then follow the displayed message to load BIOS default
setting.
3.6 WDT
Function
The algorithm of the WDT function can be simply described as a timer counting
process with an output event. The Time-Out period ( Twd ) can be set by software
commands or hardware jumpers that depend on the board circuit design and may be
different among the boards. This timer can be used to monitor a software hang.
PEB-2738 allows users to control WDT by issuing dynamic software commands.The
WDT starts counting when it is activated. It will cause a system reset once it expires.
Before WDT expires, a refreshing command with a Twd can be issued to re-count
WDT and continue the status monitoring. If the system encounters a software or
application hang, WDT will generate a system reset after its timeout.
The related Control Registers of WDT are included in the following programming
guide that is written in C language. User can write a non-zero value ( defined as
Twd ) into the Time-out Value Register ( CR_Twd ) to enable WDT. Users can write
0x00 and then Twd to CR_Twd to refresh WDT. To refresh WDT, the time tolerance
of refreshing interval must be considered. The smaller of Twd, the more deviation of
WDT and you need to include more tolerance. “Let Twd be longer than 2 seconds” is
the recommendation due to the limitation of Winbond W83627DHG WDT. You can
call Portwell support center for reference. The value read back from CR_Twd
indicates the counting down value instead of the original Twd. System will be reset
after the Time-out Value to be counted down to zero. Users can directly fill a zero
value into CR_Twd to disable WDT immediately. To ensure a successful access to
the desired Control Register, the following programming guide should be followed.
Programming guide :
