ACT-08A-N270 Access Control Terminal
Page 145
NOTE:
The following discussion applies to DOS environment. IEI support is
contacted or the IEI website visited for specific drivers for more
sophisticated operating systems, e.g., Windows and Linux.
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 EMI 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. While 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 ACT-08A-N270
Страница 15: ...ACT 08A N270 Access Control Terminal Page 15 1 Introduction Chapter 1 ...
Страница 24: ...ACT 08A N270 Access Control Terminal Page 24 2 Detailed Specifications Chapter 2 ...
Страница 34: ...ACT 08A N270 Access Control Terminal Page 34 3 Unpacking Chapter 3 ...
Страница 37: ...ACT 08A N270 Access Control Terminal Page 37 4 Installation Chapter 4 ...
Страница 63: ...ACT 08A N270 Access Control Terminal Page 63 5 RFID Reader Chapter 5 ...
Страница 77: ...ACT 08A N270 Access Control Terminal Page 77 6 System Maintenance Chapter 6 ...
Страница 85: ...ACT 08A N270 Access Control Terminal Page 85 7 AMI BIOS Setup Chapter 7 ...
Страница 128: ...ACT 08A N270 Access Control Terminal Page 128 A System Specifications Appendix A ...
Страница 132: ...ACT 08A N270 Access Control Terminal Page 132 B External Connector Pinouts Appendix B ...
Страница 136: ...ACT 08A N270 Access Control Terminal Page 136 C Safety Precautions Appendix C ...
Страница 140: ...ACT 08A N270 Access Control Terminal Page 140 D BIOS Configuration Options Appendix D ...
Страница 144: ...ACT 08A N270 Access Control Terminal Page 144 E Watchdog Timer Appendix E ...
Страница 147: ...ACT 08A N270 Access Control Terminal Page 147 F Hazardous Materials Disclosure Appendix F ...