Hector Martin wrote:
> What, if anything, should I add to the PIC's inputs to protect it from 
> EMI, static, and the like? This is a one-off project, and minimum cost 
> is not critical. I've been thinking about a bunch of optocouplers - 
> these should nicely isolate the PIC from anything and everything on the 
> outside, and I don't expect the LEDs to have any problems operating 
> under these conditions. Any other ideas / suggestions?

I'd just place a R-C in series/parallel: make it some 100-470ohm, and
10-100nF (don't know how fast those pushbuttons have to react).
I don't think optocouplers are needed.

> Along similar lines, I need to run an RS232 link from a PC to the PIC. 
> I'm using a MAX232 transceiver, as usual. Data rate isn't very high; 
> 9600baud should suffice. What would be the maximum length of the wiring 
> under these conditions? Shielded vs. unshielded cabling, etc?

IMO, even 50-100mt or more, even with unshielded cabling. If you need
more, 485 differential signaling should take you up to 250+ mt.

-- 
Ciao, Dario







-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist