At 08:36 AM 10/05/2010, you wrote:
>Isaac Marino Bavaresco wrote:
> > I had an event where the WDT didn't help. After a surge, something
> > latched-up inside the PIC and not even the WDT could fix. The chip
> > heated a little, but after power down and some time to cool, it worked
> > OK. Of course we replaced the chip anyway.
>
>Sounds like it could have been a glitch on Vdd so that momemtarily some pins
>were more than a diode drop above Vdd, which caused the chip to become a
>SCR.

Right, in which case nothing short of cycling the power would clear
such a fault. In some cases making provision for cycling the power,
as well as properly implementing a WDT, is the only way to get
acceptable reliability.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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