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What is the Watch Dog Timer?

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vicky29

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Watch Dog Timer

Hi friends,
What is "Watch Dog Timer" ? where is it used? actually i've heard a lot about it but don't know what it is........

Thanks
 

Re: Watch Dog Timer

It is a concept (maybe implemented as software and/or hardware).

Whenever there have a dead loop or other issue, the system will reset itself to exit from the dead loop. There should be many different types of implementation.
 

Re: Watch Dog Timer

Hello

I have seen many guys suffering from watchdog timers, although the idea of watchgod timer is so simple to understand, really.

In PICs, the watchdog timer is an 8-bit counter that receives its clock from the processor clock, you can also divide the clock that is going to drive the watchdog timer using a postscaler/prescaler, not sure which one exactly, as I remember.

Now, the only thing that happens is when the watchdog has reached 255 is that it resets the PIC, indicating that there is a dead loop in your code, or the PIC is not working fine with your code.

Usually the watchdog timer, if enabled shall not reset the PIC, as you have to use "CLRWDT" command many times among your code lines to make sure that watchdog timer never counts to 255, if it happens and the PIC has entered a code that it can't get out from, and there is not "CLRWDT" command, the watchdog timer will reset the PIC for sure.

Kind day
 

Re: Watch Dog Timer

Hi


Here is a link for EDN artical describing wd timer

**broken link removed**


All the best

Bobi
 

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