Ampro Corporation XTX 820 - Manual (Page 63)

Chapter 3 Hardware
XTX 820 Reference Manual 57
To ensure the impact on processor performance is reduced to a minimum, the TCC can only be active for
short periods of time, which requires a properly designed thermal solution. The Intel Pentium/Celeron
M processor datasheet can provide you with more information.
The thermal trip signal is used by Intel's Pentium/Celeron M processors for catastrophic thermal
protection. If the processor's silicon reaches a temperature of approximately 125°C then the processor's
thermal trip signal will go active and the system will automatically shut down to prevent any damage to
the processor as a result of overheating. The thermal trip signal activation is completely independent
from processor activity and therefore does not produce any bus cycles.
NOTE An ATX power supply is required to make use of the thermal trip
signal and automatically switch off the system.
Watchdog Timer (WDT)
The watchdog timer (WDT) restarts the system if an error or mishap occurs, allowing the system to
recover from the mishap, even though the error condition may still exist. Possible problems include
failure to boot properly, the application software’s loss of control, failure of an interface device,
unexpected conditions on the bus, or other hardware or software malfunctions.
The WDT (watchdog timer) can be used both during the boot process and during normal system
operation.
• During the Boot process – If the operating system fails to boot in the time interval set in the
BIOS, the system will reset.
The watchdog timer (WDT) is enabled and configured in the BIOS Setup Utility screen, Advanced
BIOS Features. Set the WDT for a time-out interval in seconds or minutes (between 30 sec to 30
min) in the Advanced BIOS Features screen. Ensure you allow enough time for the boot process to
complete and for the OS to boot. The OS or application must tickle (reset) the WDT before the
timer expires. This can be done by accessing the hardware directly or through a BIOS call.
• During System Operation – An application can set up the WDT hardware through a BIOS call, or
by accessing the hardware directly. Some Ampro Board Support Packages provide an API
interface to the WDT. The application must tickle (reset) the WDT before the timer expires or
the system will be reset.
• Watchdog Setup – Ampro has provided a System Utility which helps you set up the WDT. The
System Utility and its user guide are located on the XTX 820 Doc & SW CD-ROM. Refer also
to Ampro's Watchdog Timer Application Note.