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System Management: IPMC Watchdog Timer Commands
10007175-02 KAT4000 User’s Manual
9-29
Monitor Support for Watchdog Timer
If a system “Warm Reset” occurs, the watchdog timer may still be running while the moni-
tor executes POST. Therefore, the monitor should take steps to stop or restart the watch-
dog timer early in POST. Otherwise, the timer may expire later during POST or after the OS
has booted.
Reset Watchdog Timer Command
The Reset Watchdog Timer command is used for starting and restarting the Watchdog
Timer from the initial countdown value that was specified in the Set Watchdog Timer com-
mand.
If a pretime-out interrupt has been configured, the Reset Watchdog Timer command will
not restart the timer once the pretime-out interval has been reached. The only way to stop
the timer once it has reached this point is via the Set Watchdog Timer command.
Table 9-31: Reset Watchdog Timer Command
Set Watchdog Timer Command
The Set Watchdog Timer command is used for initializing and configuring the watchdog
timer. The command is also used for stopping the timer.
If the timer is already running, the Set Watchdog Timer command stops the timer (unless
the “don’t stop” bit is set) and clears the Watchdog pretime-out interrupt flag (see Get
Message Flags command in the IPMI specification v1.5). IPMC hard resets, system hard
resets, and the Cold Reset command also stop the timer and clear the flag.
Byte 1: This selects the timer use and configures whether an event will be logged on expiration.
Byte 2: This selects the time-out action and pretime-out interrupt type.
Byte 3: This sets the pretime-out interval. If the interval is set to zero, the pretime-out action
occurs concurrently with the time-out action.
Byte 4: This clears the Timer Use Expiration flags. A bit set in byte 4 of this command clears the cor-
responding bit in byte 5 of the Get Watchdog Timer command.
Bytes 5 and 6: These hold the least significant and most significant bytes, respectfully, of the countdown
value. The Watchdog Timer decrement is one count/100 ms. The counter expires when the
count reaches zero. If the counter is loaded with zero and the Reset Watchdog command is
issued to start the timer, the associated timer events occur immediately.
Type: Byte: Data Field:
Request Data — —
Response Data 1 Completion Code