7 utilities, 1 watchdog timer, Using the watchdog in an application – ADLINK cPCI-3965 User Manual

Page 57: Chapter 7, utilities, Watchdog timer, 7utilities

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Utilities

43

cPCI-3965

7

Utilities

7.1

Watchdog Timer

This section describes the operation of the cPCI-3965’s watchdog

timer (WDT). The primary function of the WDT is to monitor the

cPCI-3965's operation and to reset the system if a software appli-

cation fails to function as programmed. The following WDT func-

tions may be controlled using a software application:

X

enabling and disabling

X

reloading timeout value

The cPCI-3965 custom WDT circuit is implemented using the

internal I/O of the ITE SuperIO IT8712F which is at 2Eh of LPC.

The basic functions of the WDT include:

X

Starting the timer countdown

X

Enabling or disabling WDT

X

Enabling or disabling WDT countdown LED ON

X

Reloading the timeout value to keep the watchdog from tim-

ing out

X

Setting the range of the timeout period from 1 to 15300 seconds

X

Sending a RESET signal to the system when the watchdog

times out

Using the Watchdog in an Application

The following section describes using the WDT functions in an

application. The WDT reset function is explained in the previous

section. This can be controlled through the registers in the cPCI-

3965's SuperIO.
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.
For a detailed programming sample, refer to the sample code pro-

vided in the ADLINK All-In-One CD. You can find it in the following

directory: X:\cPCI\cPCI-3965\WDT.

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