WAFER-ULT/ULT2-i1 3.5" SBC
Page 145
NOTE:
The following discussion applies to DOS environment. Contact IEI support
or visit the IEI website for specific drivers for other operating systems.
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 EMIs 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 E-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. When 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 WAFER-ULT-i1
Page 9: ...WAFER ULT ULT2 i1 3 5 SBC Page ix E WATCHDOG TIMER 144 F HAZARDOUS MATERIALS DISCLOSURE 147...
Page 16: ...WAFER ULT ULT2 i1 3 5 SBC Page 1 Chapter 1 1 Introduction...
Page 21: ...WAFER ULT ULT2 i1 3 5 SBC Page 6 Figure 1 3 WAFER ULT ULT2 i1 Dimensions mm...
Page 26: ...WAFER ULT ULT2 i1 3 5 SBC Page 11 Chapter 2 2 Packing List...
Page 31: ...WAFER ULT ULT2 i1 3 5 SBC Page 16 Chapter 3 3 Connectors...
Page 64: ...WAFER ULT ULT2 i1 3 5 SBC Page 49 Chapter 4 4 Installation...
Page 88: ...WAFER ULT ULT2 i1 3 5 SBC Page 73 Chapter 5 5 BIOS...
Page 127: ...WAFER ULT ULT2 i1 3 5 SBC Page 112 6 Software Drivers Chapter 6...
Page 147: ...WAFER ULT ULT2 i1 3 5 SBC Page 132 Appendix A A Regulatory Compliance...
Page 149: ...WAFER ULT ULT2 i1 3 5 SBC Page 134 Appendix B B BIOS Options...
Page 152: ...WAFER ULT ULT2 i1 3 5 SBC Page 137 Appendix C C Terminology...
Page 156: ...WAFER ULT ULT2 i1 3 5 SBC Page 141 Appendix D D Digital I O Interface...
Page 159: ...WAFER ULT ULT2 i1 3 5 SBC Page 144 Appendix E E Watchdog Timer...
Page 162: ...WAFER ULT ULT2 i1 3 5 SBC Page 147 Appendix F F Hazardous Materials Disclosure...
