Series resistance would server you better for ESD protection. Most low
frequency signals could handle 1K in series, but even 100 Ohms would help.
Options are quite limited on other pins like the oscillator input.

Is it possible to put the PCB into an enclosure? That way, all internal
signals would not be an issue. You would only need to protect the signals
that made their way out the enclosure.

David

 

> -----Original Message-----
> From: wouter van ooijen [mailto:wouter@voti.nl] 
> Sent: Saturday, February 16, 2008 5:07 PM
> To: piclist@mit.edu
> Subject: [PIC]
> 
> I use PICs in classes. The PICs are on a PCB, but otherwise 
> unprotected.
> The students buy the PCBs, so they can work at home. Informatics
> students can not be expected to know much about static electricity, so
> for all I know they might use it to comb their cat's hairs. I 
> have hadd
> some pretty weird failures previous years, so it might be a 
> good idea to
> put some form of protection on all PIC pins. My idea is a resistor to
> ground for each pin, but what value? Would 1M be sufficient, or should
> it be lower?
> 
> And what about the one pins that probably won't like any 
> load, even 1M:
> the oscillator input? 
> 
> Wouter van Ooijen
> 
> -- -------------------------------------------
> Van Ooijen Technische Informatica: www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: www.voti.nl/hvu
>  
>  
> 
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