WAFER-BW SBC
Page 118
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-BW-N4-R10
Page 14: ......
Page 15: ...WAFER BW SBC Page 1 Chapter 1 1 Introduction...
Page 19: ...WAFER BW SBC Page 5 1 5 Dimensions The dimensions of the board are listed below...
Page 20: ...WAFER BW SBC Page 6 Figure 1 3 Dimensions with Heat Spreader mm...
Page 25: ...WAFER BW SBC Page 11 Chapter 2 2 Unpacking...
Page 29: ...WAFER BW SBC Page 15 Chapter 3 3 Connectors...
Page 59: ...WAFER BW SBC Page 45 Chapter 4 4 Installation...
Page 77: ...WAFER BW SBC Page 63 Chapter 5 5 BIOS...
Page 117: ...WAFER BW SBC Page 103 Chapter 6 6 Software Drivers...
Page 121: ...WAFER BW SBC Page 107 Appendix A A Regulatory Compliance...
Page 123: ...WAFER BW SBC Page 109 B Product Disposal Appendix B...
Page 125: ...WAFER BW SBC Page 111 Appendix C C BIOS Menu Options...
Page 128: ...WAFER BW SBC Page 114 Appendix D D Digital I O Interface...
Page 131: ...WAFER BW SBC Page 117 Appendix E E Watchdog Timer...
Page 134: ...WAFER BW SBC Page 120 Appendix F F Hazardous Materials Disclosure...