Difference between revisions of "Example watchdog"
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| − | {{todo| | + | {{todo|Complete (01.03.14-11:32->JG+);(01.03.14-11:42->MD-);(02.04.14-19:30->MD);(02.06.14-17:32->BS+);(02.06.14-19:15->MD+);(04.07.14-10:15->BS+);(04.10.14-11:50->BS+);(11.10.15-15:30->MG+)|Brian Serrano|project=oe 4,oe 5,bs,md,SEOKWREV,Complete}} |
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| + | {{#seo: | ||
| + | |title=Example watchdog | ||
| + | |titlemode=append | ||
| + | |keywords=Example watchdog,watchdog timer,watchdog test,Linux watchdog | ||
| + | |description=This is a guide to the <code>watchdog</code> C example project included in the EMAC OE SDK. | ||
| + | }} | ||
This is a guide to the <code>watchdog</code> C example project included in the EMAC OE SDK. | This is a guide to the <code>watchdog</code> C example project included in the EMAC OE SDK. | ||
| − | A | + | 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. |
| + | |||
| + | For more information about the protocol see the following page: http://en.wikipedia.org/wiki/Watchdog_timer | ||
The <code>watchdog</code> project builds one executable: <code>watchdog-test</code>. | The <code>watchdog</code> project builds one executable: <code>watchdog-test</code>. | ||
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== Opening, Building and Uploading the Project Files == | == Opening, Building and Uploading the Project Files == | ||
| − | < | + | For information on opening the project from within Eclipse, please see [[Importing the EMAC OE SDK Projects with Eclipse]]. Then, follow [[Using the EMAC OE SDK Projects with Eclipse]] for information on how to build, upload and execute the example. |
| + | |||
| + | Alternatively, the <code>Makefile</code> can be used with the <code>make</code> command from the commandline to build and upload the example. For information on this method, please see [[Using EMAC OE SDK Example Projects]]. | ||
| + | |||
| + | ====EMAC SDK 5.X==== | ||
| + | |||
| + | For information on opening the project from within QtCreator, please see [[Getting_Started_With_Qt_Creator#Adding_Source_Files | QtCreator: Adding Source Files]]. Then, follow [[Getting Started With Qt Creator]] for information on how to build, upload and execute the example. | ||
| + | |||
| + | Alternatively, the <code>CMakefile.txt</code> can be used with the <code>cmake</code> command from the commandline to build and upload the example. For information on this method, please see [[Getting_Started_with_the_EMAC_OE_SDK#Target_Machine_Compiling | Getting Started with the EMAC OE SDK]]. | ||
| + | Code can be found at http://git.emacinc.com/OE/example-projects | ||
==Usage and Behavior== | ==Usage and Behavior== | ||
| − | <code>watchdog</code> | + | A '''watchdog timer''' is a hardware circuit that can reset the computer system in case of a software fault. The <code>watchdog-test</code> application can enable, disable, activate, configure and interrupt the '''watchdog timer'''. |
| + | {{note| Activating watchdog invokes system reset (after timeout)}} | ||
===Hardware Requirements=== | ===Hardware Requirements=== | ||
| − | + | <code>watchdog</code> will run on any system for which it can be compiled and implements the standard Linux <code>watchdog</code> API. | |
===<code>watchdog</code> Usage=== | ===<code>watchdog</code> Usage=== | ||
| − | + | {{cli | ./watchdog-test [-det] | hostname=emac-oe}} | |
| − | + | ;-d:Disable watchdog. | |
| − | + | ;-e:Enable watchdog. | |
| − | + | ;-t:Set the watchdog timeout (to a value specified in code. Default is five seconds). | |
===Usage Example. Activating <code>watchdog</code> with a periodic interrupt=== | ===Usage Example. Activating <code>watchdog</code> with a periodic interrupt=== | ||
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This will activate <code>watchdog</code> and initiate a periodic interrupt to keep it from timing out. | This will activate <code>watchdog</code> and initiate a periodic interrupt to keep it from timing out. | ||
| − | + | {{clo}} | |
| − | + | {{clio | pwd=/tmp | hostname=emac-oe | ./watchdog-test }} | |
Watchdog Ticking Away! | Watchdog Ticking Away! | ||
| − | + | {{clos}} | |
| − | + | Every second <code>watchdog-test</code> is sending an IOCTL to the watchdog driver, which in turn ticks <code>watchdog</code> to reset its internal timer so it doesn't timeout and trigger a system reset. | |
| − | |||
| − | Now we will stop interrupting <code>watchdog</code> and let it trigger a computer reset | + | Now we will stop interrupting <code>watchdog</code> and let it trigger a computer reset by pressing ''Ctrl+C''. |
| − | |||
| − | |||
===Usage Example. Disabling <code>watchdog</code>=== | ===Usage Example. Disabling <code>watchdog</code>=== | ||
| − | + | {{clo}} | |
| − | + | {{clio | pwd=/tmp | hostname=emac-oe | ./watchdog-test -d }} | |
Watchdog card disabled. | Watchdog card disabled. | ||
| − | + | {{clos}} | |
| − | . | + | After running the <code>./watchdog-test -d</code> command, the program exits normally. |
===Usage Example. Enabling <code>watchdog</code>=== | ===Usage Example. Enabling <code>watchdog</code>=== | ||
| − | This will activate <code>watchdog</code> but it won't perform a periodic timeout interrupt (see the first usage example). So when you run it the program activates <code>watchdog</code> and then <code>watchdog</code> resets the system. | + | This will enable and activate <code>watchdog</code> but it won't perform a periodic timeout interrupt (see the first usage example, above). So when you run it the program activates <code>watchdog</code> and then <code>watchdog</code> resets the system. |
| − | + | {{clo}} | |
| − | + | {{clio | pwd=/tmp | hostname=emac-oe | ./watchdog-test -e }} | |
Watchdog card enabled. | Watchdog card enabled. | ||
| − | + | {{clos}} | |
| − | . | + | After running the <code>./watchdog-test -e</code> command, the system resets. |
===Usage Example. Setting <code>watchdog</code> timeout=== | ===Usage Example. Setting <code>watchdog</code> timeout=== | ||
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This will activate <code>watchdog</code> and set it to timeout in 5 seconds. | This will activate <code>watchdog</code> and set it to timeout in 5 seconds. | ||
| − | + | {{clo}} | |
| − | + | {{clio | pwd=/tmp | hostname=emac-oe | ./watchdog-test -t }} | |
Watchdog timeout set to 5 seconds! | Watchdog timeout set to 5 seconds! | ||
| − | |||
| − | . | + | {{clos}} |
| + | |||
| + | After running the <code>./watchdog-test -t</code> command, the program exits normally. Once it exits, 5 seconds will elapse, and then the system resets. | ||
| + | |||
| + | ==Summary== | ||
| + | |||
| + | The <code>watchdog</code> C example project demonstrates how to use the '''watchdog timer'''. The '''watchdog timer''' is there to help ensure that your system will return to a functional state should your program get stuck while executing. | ||
| + | |||
| + | EMAC provides examples of how to enable, disable, activate, configure and interrupt the <code>watchdog</code> hardware circuit. To use <code>watchdog</code> peripheral in Linux you will need a <code>watchdog</code> driver, and a <code>watchdog</code> device file. A device file is a special kind of virtual file which marks the device node in your root filesystem. Normally it's called <code>/dev/watchdog</code> . | ||
Latest revision as of 13:22, 30 November 2022
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.
For more information about the protocol see the following page: http://en.wikipedia.org/wiki/Watchdog_timer
The watchdog project builds one executable: watchdog-test.
Opening, Building and Uploading the Project Files
For information on opening the project from within Eclipse, please see Importing the EMAC OE SDK Projects with Eclipse. Then, follow Using the EMAC OE SDK Projects with Eclipse for information on how to build, upload and execute the example.
Alternatively, the Makefile can be used with the make command from the commandline to build and upload the example. For information on this method, please see Using EMAC OE SDK Example Projects.
EMAC SDK 5.X
For information on opening the project from within QtCreator, please see QtCreator: Adding Source Files. Then, follow Getting Started With Qt Creator for information on how to build, upload and execute the example.
Alternatively, the CMakefile.txt can be used with the cmake command from the commandline to build and upload the example. For information on this method, please see Getting Started with the EMAC OE SDK.
Code can be found at http://git.emacinc.com/OE/example-projects
Usage and Behavior
A watchdog timer is a hardware circuit that can reset the computer system in case of a software fault. The watchdog-test application can enable, disable, activate, configure and interrupt the watchdog timer.
| NOTE |
| Activating watchdog invokes system reset (after timeout) |
Hardware Requirements
watchdog will run on any system for which it can be compiled and implements the standard Linux watchdog API.
watchdog Usage
root@emac-oe:~# ./watchdog-test [-det] - -d
- Disable watchdog.
- -e
- Enable watchdog.
- -t
- Set the watchdog timeout (to a value specified in code. Default is five seconds).
Usage Example. Activating watchdog with a periodic interrupt
This will activate watchdog and initiate a periodic interrupt to keep it from timing out.
root@emac-oe:/tmp# ./watchdog-test Watchdog Ticking Away!
Every second watchdog-test is sending an IOCTL to the watchdog driver, which in turn ticks watchdog to reset its internal timer so it doesn't timeout and trigger a system reset.
Now we will stop interrupting watchdog and let it trigger a computer reset by pressing Ctrl+C.
Usage Example. Disabling watchdog
root@emac-oe:/tmp# ./watchdog-test -d Watchdog card disabled.
After running the ./watchdog-test -d command, the program exits normally.
Usage Example. Enabling watchdog
This will enable and activate watchdog but it won't perform a periodic timeout interrupt (see the first usage example, above). So when you run it the program activates watchdog and then watchdog resets the system.
root@emac-oe:/tmp# ./watchdog-test -e Watchdog card enabled.
After running the ./watchdog-test -e command, the system resets.
Usage Example. Setting watchdog timeout
This will activate watchdog and set it to timeout in 5 seconds.
root@emac-oe:/tmp# ./watchdog-test -t Watchdog timeout set to 5 seconds!
After running the ./watchdog-test -t command, the program exits normally. Once it exits, 5 seconds will elapse, and then the system resets.
Summary
The watchdog C example project demonstrates how to use the watchdog timer. The watchdog timer is there to help ensure that your system will return to a functional state should your program get stuck while executing.
EMAC provides examples of how to enable, disable, activate, configure and interrupt the watchdog hardware circuit. To use watchdog peripheral in Linux you will need a watchdog driver, and a watchdog device file. A device file is a special kind of virtual file which marks the device node in your root filesystem. Normally it's called /dev/watchdog .
