> > I would recomend to place small resistor i.e. 200 OHm is
> > series with PIC inputs connected to outside 0 to 5V signals
> > to limit ingoing current
> 
> That is recommended by MC in their circuit for taking /MCLR
> low with a reset switch. Jason, do you use a reset switch and,
> if so, does it take /MCLR direct to 0V ?

The correct question is "is there a >100nF cap directly on the /MCLR
pin?".

The failure mode for which this series resistor is the cure is the Vdd
dropping below /MCLR, which could cause the whole circuit to be powered
from the cap via /MCLR, which is not a mode the PIC die is designed for.

Wouter van Ooijen

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Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 

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