PPC-F12B/15B/17B/19B-BTi Panel PC
Page 131
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 D-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-F12B
Page 16: ......
Page 17: ...PPC F12B 15B 17B 19B BTi Panel PC Page 1 1 Introduction Chapter 1 ...
Page 29: ...PPC F12B 15B 17B 19B BTi Panel PC Page 13 2 Unpacking Chapter 2 ...
Page 33: ...PPC F12B 15B 17B 19B BTi Panel PC Page 17 3 Installation Chapter 3 ...
Page 75: ...PPC F12B 15B 17B 19B BTi Panel PC Page 59 Chapter 4 4 System Maintenance ...
Page 77: ...PPC F12B 15B 17B 19B BTi Panel PC Page 61 5 BIOS Setup Chapter 5 ...
Page 112: ...PPC F12B 15B 17B 19B BTi Panel PC Page 96 6 Interface Connectors Chapter 6 ...
Page 132: ...PPC F12B 15B 17B 19B BTi Panel PC Page 116 Appendix A A Regulatory Compliance ...
Page 137: ...PPC F12B 15B 17B 19B BTi Panel PC Page 121 B BIOS Configuration Options Appendix B ...
Page 140: ...PPC F12B 15B 17B 19B BTi Panel PC Page 124 C Safety Precautions Appendix C ...
Page 146: ...PPC F12B 15B 17B 19B BTi Panel PC Page 130 D Watchdog Timer Appendix D ...
Page 149: ...PPC F12B 15B 17B 19B BTi Panel PC Page 133 Appendix E E Hazardous Materials Disclosure ...