ADLINK Technology cPCI-6630 Series, User Manual

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Utilities 63
cPCI-6630
7 Utilities
7.1 Watchdog Timer
This section describes the operation of the cPCI-6630’s watch dog
timer (WDT). The primary function of the WDT is to monitor the
cPCI-6630 operation and to reset the system if a software applica-
tion fails to function as programmed. The following WDT functions
may be controlled using a software application:
X enabling and disabling
X reloading timeout value
The cPCI-6630 custom WDT circuit is implemented using the
internal IO of the ITE Super I/O IT8786 which is at 2Eh of LPC.
The basic functions of the WDT include:
X Starting the timer countdown.
X Enabling or disabling WDT.
X Enable or disable WDT countdown LED ON.
X Reloading the timeout value to keep the watch dog from
timing out.
X Setting the range of the timeout period from 1 to 15300
seconds.
X Sending a RESET signal to system when the watch dog
times out
Using the Watchdog in an Application
The following section describes the WDT functions in an applica-
tion. These can be controlled through the registers in the cPCI-
6630 Super I/O.
An application using the reset feature enables the watchdog func-
tion, sets the count-down period, and reloads the timeout value
periodically to keep it from resetting the system. If the timer count-
down value is not reloaded, the watchdog resets the system hard-
ware after its counter reaches zero.