> >This is about the inputs, I have seen in the datasheet that after
power-on
> >all the TRIS registers are set as inputs. So what is the recommended
> >practice, I suspect unused pins should be left as inputs, isn't that why
> >they are reset to inputs in the first place?
> >
> >
> They are set to INPUT at reset so that the chip isn't damaged by
> something driving the
> pin at power up.

Sorry, but what do you mean "something" ?

>
> >Secondly, what is the recommended procedure with unused pins, to
> >leave them alone, or to connect them to gnd or something, don't they
> >have a week pull up/down internally anyway?
> >
> >
> Assign unused pins as OUTPUTS usually at GND level. You can assign a
> weak pullup,
> but they are normally just floating...

Sorrry, what do you mean "they are just floating"
Are they floating because of a pullup, or because a pullup is weak,
or something else - sorry you have completely lost me now.
which pullup?

>
> >And why would touching an input would have any effect on the pic,
> >unless there is some firmware which is monitoring these pins, which
> >there isn't, I can't see why this could possibly be the reason, and
> >maybe it is a capacitance issue,  i.e normal  expected behaviour?
> >
> >
> Your body has about a 100K to 1M  resistance to GND. But more important,
> your
> body picks up stray electric fileds, such as flourescent lighting etc.
>
> I know of a PIC design that uses the fact that the human body effects
> pins WITHOUT
> TOUCHING them (just being closeby). The RC time constant of the design
> is changed
> by the presence of the finger, and is detected by the PIC. Take a peek at
> http://www.bytecraft.com/touchsw.html .

ok, this is interesting (perhaps), but how does it help me to understand if
touching
my pic should have an effect or not under proper design. Am I the only one
in the world who has noticed that (and became a tadd concerned)?

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