Example watchdog

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TODO: {{#todo:Review(01.02.14-15:25->JG+)|Jgreene|oe 4,oe 5,jg,md,Review}}

This is a guide to the watchdog C example project included in the EMAC OE SDK.

A Watchdog Timer (WDT) is a hardware circuit that can reset the computer system in case of a software fault. This is an example test for the Linux watchdog API.

The watchdog project builds one executable: watchdog-test.

Opening, Building and Uploading the Project Files

stubbooo

Usage and Behavior

watchdog

Hardware Requirements

fof ofoo

watchdog Usage

./watchdog-test [-det]
  • d Disable the watchdog card.
  • -e" to enable the watchdog card
  • -s set the watchdog timeout

Usage Example

root@som9g20:/tmp# ./watchdog-test 
Watchdog Ticking Away!

We have activated the watchdog and it's counting down to computer reset - or rather it would be if we didn't keep resetting it's timer. That's the LED on the SoM blinking at about 1 Hz. Every second watchdog-test is sending an IOCTL to the watchdog driver, which in turn ticks the watchdog to reset its internal timer so it doesn't time-out and trigger a system reset.

Now we will stop interrupting the watchdog and let it trigger a computer reset. Hit CTRL-C.

...and the system resets.