ECN-360A-D2550 Em b e d d e d S ys te m
P a g e 125
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 S u b -fu n c tio n :
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 ECN-360A-D2550
Page 12: ...ECN 360A D2550 Embedded Sys tem Page 1 Chapter 1 1 Introduction...
Page 17: ...ECN 360A D2550 Embedded Sys tem Page 6 Figure 1 3 ECN 360A D2550 Rear Panel...
Page 19: ...ECN 360A D2550 Embedded Sys tem Page 8 Chapter 2 2 Unpacking...
Page 23: ...ECN 360A D2550 Embedded Sys tem Page 12 Chapter 3 3 Ins tallation...
Page 34: ...ECN 360A D2550 Embedded Sys tem Page 23 Chapter 4 4 Sys tem Motherboard...
Page 58: ...ECN 360A D2550 Embedded Sys tem Page 47 Chapter 5 5 BIOS...
Page 86: ...ECN 360A D2550 Embedded Sys tem Page 75 A Safety Precautions Appendix A...
Page 91: ...ECN 360A D2550 Embedded Sys tem Page 80 B BIOS Menu Options Appendix B...
Page 94: ...ECN 360A D2550 Embedded Sys tem Page 83 Appendix C C One Key Recovery...
Page 102: ...ECN 360A D2550 Embedded Sys tem Page 91 Figure C 5 Partition Creation Commands...
Page 135: ...ECN 360A D2550 Embedded Sys tem Page 124 D Watchdog Timer Appendix D...
Page 138: ...ECN 360A D2550 Embedded Sys tem Page 127 Appendix E E Hazardous Materials Dis clos ure...
