Actually, if the pin is not being used, it's internal pull up should be
enabled to prevent accidental noise, or power draw.


Shawn Wilton
Junior in CpE
MicroBiologist

Phone: (503) 881-2707
Email: shawn@black9.net

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Jinx wrote:
>>>Pins that need to be inputs but at some time may be uncommitted,
>>>for example when an input device is removed/unplugged, should
>>>have a pull-up or pull-down resistor so they don't float
>>
>>Is this true for analog inputs also?
>
>
> No, I wouldn't think so. I can't see any specific advice in the manuals
> for commiting unused analogue inputs
>
> The main reason for using a p/u or p/d resistor on a digital input is to
> put it in a known state, both electrically and logically. It may not be
> important what logic level a floating pin could be at any time, but
> electrically it's not desirable because of the switching power used,
> which may affect the PIC or other components
>
> http://www.piclist.com/techref/logic/xtrapins.htm
>
> Obviously an analogue input is required to accept an indeterminate
> voltage, so I doubt if digital design rules apply
>
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