HPCIE-Q470 Half-size PICMG 1.3 CPU Card
Page 78
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 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. 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 HPCIE-Q470
Страница 11: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 11 Chapter 1 1 Introduction...
Страница 19: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 19 Chapter 2 2 Packing List...
Страница 23: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 23 Chapter 3 3 Connectors...
Страница 53: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 53 Chapter 4 4 Installation...
Страница 70: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 70 Appendix A A Regulatory Compliance...
Страница 72: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 72 B Product Disposal Appendix B...
Страница 74: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 74 Appendix C C Digital I O Interface...
Страница 77: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 77 Appendix D D Watchdog Timer...
Страница 80: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 80 Appendix E E Error Beep Code...
Страница 82: ...HPCIE Q470 Half size PICMG 1 3 CPU Card Page 82 Appendix F F Hazardous Materials Disclosure...