PPC-FxxA-H81 Panel PC
Page 158
NOTE:
The following discussion applies to DOS environment. IEI support is
contacted or the IEI website visited for specific drivers for more
sophisticated operating systems, e.g., Windows and Linux.
The Watchdog Timer is provided to ensure that standalone systems can always recover
from catastrophic conditions that cause the CPU to crash. This condition may have
occurred by external EMI or a software bug. When the CPU stops working correctly,
Watchdog Timer either performs a hardware reset (cold boot) or a Non-Maskable Interrupt
(NMI) to bring the system back to a known state.
A BIOS function call (INT 15H) is used to control the Watchdog Timer:
INT 15H:
AH – 6FH Sub-function:
AL – 2:
Sets the Watchdog Timer’s period.
BL:
Time-out value (Its unit-second is dependent on the item “Watchdog
Timer unit select” in CMOS setup).
Table C-1: AH-6FH Sub-function
Call sub-function 2 to set the time-out period of Watchdog Timer first. If the time-out value
is not zero, the Watchdog Timer starts counting down. While the timer value reaches zero,
the system resets. To ensure that this reset condition does not occur, calling sub-function
2 must periodically refresh the Watchdog Timer. However, the Watchdog timer is disabled
if the time-out value is set to zero.
A tolerance of at least 10% must be maintained to avoid unknown routines within the
operating system (DOS), such as disk I/O that can be very time-consuming.
Summary of Contents for PPC-FxxA-H81
Page 14: ...PPC FxxA H81 Panel PC Page 1 1 Introduction Chapter 1 ...
Page 20: ...PPC FxxA H81 Panel PC Page 7 Figure 1 4 Bottom View ...
Page 28: ...PPC FxxA H81 Panel PC Page 15 2 Unpacking Chapter 2 ...
Page 32: ...PPC FxxA H81 Panel PC Page 19 3 Installation Chapter 3 ...
Page 69: ...PPC FxxA H81 Panel PC Page 56 Chapter 4 4 System Maintenance ...
Page 75: ...PPC FxxA H81 Panel PC Page 62 5 BIOS Setup Chapter 5 ...
Page 113: ...PPC FxxA H81 Panel PC Page 100 6 Driver Installation Chapter 6 ...
Page 142: ...PPC FxxA H81 Panel PC Page 129 7 Interface Connectors Chapter 7 ...
Page 162: ...PPC FxxA H81 Panel PC Page 149 A BIOS Configuration Options Appendix A ...
Page 165: ...PPC FxxA H81 Panel PC Page 152 B Safety Precautions Appendix B ...
Page 170: ...PPC FxxA H81 Panel PC Page 157 C Watchdog Timer Appendix C ...
Page 173: ...PPC FxxA H81 Panel PC Page 160 D Hazardous Materials Disclosure Appendix D ...