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Could someone help me to interface PIC24 for instance with a external watchdog? http://datasheets.maximintegrated.com/en/ds/MAX823-MAX825Z.pdf

A kind of beta version could be : WDI=1; while(1) { if(wdi!=0) routine execution break }

But I don't know how could reset it .

Can someone gives me an idea?

Căpățînă Alexandru Ioan
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1 Answers1

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The /RESET pin of the MAX82X must be connected to the /RESET pin of your PIC24.

The WDI of the MAX82X must be connected a GPIO of your PIC24.

In the main loop, you need to toggle the GPIO to kick the watchdog. The datasheet says that the pulse should be minimum 50ns and that the watchdog timer is 1.6s. This means that you need to make sure that the GPIO is toggled within 1.6s.

The most simple way is:

int main(void)
{
    hardware_init(); //Set up GPIO

    while(1)
    {
        toggle_gpio(); //Kick watchdog

        //Your app
    }
}

If you app takes more than 1.6s to process, you will need to toggle the gpio within your app as well.

If you fail to kick the watchdog (ie toggle the IO) within 1.6s, the MAX82X will reset your PIC24.

Guillaume Michel
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