IEI Technology ROCKY-6160, Руководство пользователя

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Appendix A. Watchdog Timer
The Watchdog Timer is provided to ensure that standalone
systems can always recover from catastrophic conditions that
cause CPU crash, e.g. external EMI or a software bug. When
the CPU stops working properly, a hardware reset (cold boot) or
a NMI (Non-Maskable Interrupt) will be issued to resume the
system 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: Set the Watchdog Timer period
BL: Time-out value (the time unit - second or
minute, is dependent on the Watchdog Timer
unit selected in BIOS setup).
You have to call sub-function 2 to set the time-out period of
Watchdog Timer first. If the time-out value is not zero,
Watchdog Timer will start counting down. When the timer value
reaches zero, the system will reset. To ensure that this reset
condition does not occur, Watchdog timer must be periodically
refreshed by calling sub-function 2. However, Watchdog timer
will be disabled if you set the time-out value to be 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
Note: When exiting a program, it is necessary to disable the
Watchdog Timer. Otherwise the system will reset.