PCISA-BT CPU Card
Page 115
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.
Содержание PCISA-BT
Страница 14: ......
Страница 15: ...PCISA BT CPU Card Page 1 Chapter 1 1 Introduction...
Страница 24: ...PCISA BT CPU Card Page 10 Chapter 2 2 Packing List...
Страница 29: ...PCISA BT CPU Card Page 15 Chapter 3 3 Connectors...
Страница 63: ...PCISA BT CPU Card Page 49 Chapter 4 4 Installation...
Страница 79: ...PCISA BT CPU Card Page 65 Chapter 5 5 BIOS...
Страница 115: ...PCISA BT CPU Card Page 101 6 Software Drivers Chapter 6...
Страница 118: ...PCISA BT CPU Card Page 104 Appendix A A Regulatory Compliance...
Страница 120: ...PCISA BT CPU Card Page 106 B Product Disposal Appendix B...
Страница 122: ...PCISA BT CPU Card Page 108 Appendix C C BIOS Options...
Страница 125: ...PCISA BT CPU Card Page 111 Appendix D D Digital I O Interface...
Страница 128: ...PCISA BT CPU Card Page 114 Appendix E E Watchdog Timer...
Страница 131: ...PCISA BT CPU Card Page 117 Appendix F F Error Beep Code...
Страница 133: ...PCISA BT CPU Card Page 119 Appendix G G Hazardous Materials Disclosure...