ADLINK Express-HRR - Manual (Page 35)

Chapter 3 Hardware
Express-HRR Reference Manual 31
Watchdog Timer
The Watchdog Timer (WDT) restarts the system if a mishap occurs, ensuring proper start-up after the
interruption. 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.
Use the ADLINK Intelligent Device Interface (AIDI) Library to configure the WDT interface. AIDI driver
information is available on the COM Express Product page at: http://www.adlinktech.com . An AIDI demo
program and the AIDI User’s Manual showing how to use the WDT function also reside in the Utilities areas
of the COM Express Product page.
The WDT (Watchdog Timer) can be used both during the boot process and during normal system operation.
• During the Boot process – If the OS fails to boot in the time interval set in the BIOS, the system will
reset.
Enable the WDT in the Custom Configuration Screen of BIOS Setup. Set the WDT for a time-out
interval in seconds, between 1 and 255, in one second increments. Ensure you allow enough time for the
boot process to complete and for the OS to boot. The OS or application must tickle the WDT as soon as
it comes up. This can be done by accessing the hardware directly or through a BIOS call.
• During System Operation – The user can set up the WDT hardware through a BIOS call or by accessing
the hardware directly using the AIDI Library. The BIOS call must tickle the WDT in the time set when
the WDT is initialized or the system will be reset.
• Watchdog Code example – ADLINK provides a source code example (AIDI demo program) on the
Express-HRR Product page of the web site illustrating how to control the WDT. The code example can
be easily copied to your development environment to compile and test or make any desired changes
before compiling.
TPM (Trusted Platform Module)
The Express-HRR provides a hardware chip called a Trusted Platform Module which is dedicated for
security functions. Trusted Computing is an industry standard created for personal computer security. The
BIOS allows you to enable or disable the TPM.
Hardware Voltage and Temperature Monitor
The Express-HRR provides a hardware monitor to ensure the health of your embedded system with built-in
support for monitoring and control of system temperatures, fan speeds, and critical module voltage levels.
The AIDI Library provides simple APIs at the application level to support these functions and adds alarm
functions when voltage or temperature levels exceed the upper or lower limits set by the user. AIDI driver
information for the Express-HRR is available on the COM Express Product page at:
http://www.adlinktech.com . An AIDI demo program and the AIDI User’s Manual showing how to use the
Hardware Monitor also reside in the Utilities areas of the COM Express Product page.
C104 VCC_12V D104 VCC_12V
C105 VCC_12V D105 VCC_12V
C106 VCC_12V D106 VCC_12V
C107 VCC_12V D107 VCC_12V
C108 VCC_12V D108 VCC_12V
C109 VCC_12V D109 VCC_12V
C110 GND D110 GND
Table 3-6. COM Express C-D Connector Signal Descriptions (Continued)