WAFER-ULT5 SBC
Page 111
NOTE:
The following discussion applies to DOS. Contact IEI support or visit the IEI
website for drivers for other operating systems.
The Watchdog Timer is a hardware-based timer that attempts to restart the system when it
stops working. The system may stop working because of external EMI or software bugs.
The Watchdog Timer ensures that standalone systems like ATMs will automatically
attempt to restart in the case of system problems.
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-ULT5
Page 13: ...WAFER ULT5 SBC Page 1 Chapter 1 1 Introduction...
Page 21: ...WAFER ULT5 SBC Page 9 Chapter 2 2 Unpacking...
Page 25: ...WAFER ULT5 SBC Page 13 Chapter 3 3 Connectors...
Page 54: ...WAFER ULT5 SBC Page 42 Chapter 4 4 Installation...
Page 71: ...WAFER ULT5 SBC Page 59 Chapter 5 5 BIOS...
Page 109: ...WAFER ULT5 SBC Page 97 Chapter 6 6 Software Drivers...
Page 112: ...WAFER ULT5 SBC Page 100 Appendix A A Regulatory Compliance...
Page 114: ...WAFER ULT5 SBC Page 102 B Product Disposal Appendix B...
Page 116: ...WAFER ULT5 SBC Page 104 Appendix C C BIOS Menu Options...
Page 119: ...WAFER ULT5 SBC Page 107 Appendix D D Digital I O Interface...
Page 122: ...WAFER ULT5 SBC Page 110 Appendix E E Watchdog Timer...
Page 125: ...WAFER ULT5 SBC Page 113 Appendix F F Error Beep Code...
Page 127: ...WAFER ULT5 SBC Page 115 Appendix G G Hazardous Materials Disclosure...
