SPCIE-C236 Full-size PICMG 1.3 CPU Card
Page 140
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 F-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 SPCIE-C236
Page 9: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page ix G HAZARDOUS MATERIALS DISCLOSURE 142...
Page 16: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 1 Chapter 1 1 Introduction...
Page 25: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 10 Chapter 2 2 Packing List...
Page 31: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 16 Chapter 3 3 Connectors...
Page 63: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 48 Chapter 4 4 Installation...
Page 89: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 74 Chapter 5 5 BIOS...
Page 136: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 121 6 Software Drivers Chapter 6...
Page 139: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 124 Appendix A A Regulatory Compliance...
Page 141: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 126 B Product Disposal Appendix B...
Page 143: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 128 Appendix C C BIOS Options...
Page 147: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 132 Appendix D D Terminology...
Page 151: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 136 Appendix E E Digital I O Interface...
Page 154: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 139 Appendix F F Watchdog Timer...
Page 157: ...SPCIE C236 Full size PICMG 1 3 CPU Card Page 142 Appendix G G Hazardous Materials Disclosure...