spare pins on a micro

[Storic]

Just a quick question,
is it better to ground any unused PINs or just leave them floating.
I an using the 24FJ256(BG)106 I will be using about 1/2 on a particular project.

Or can I have the unused pins float with them internally grounded.
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What has been learnt if you make the same mistake?

[newguy]

Set unused pins to be outputs and force them either high or low - it doesn't matter. Don't externally connect them to anything on the PCB - just leave their pads unconnected. Never let them float as inputs as they can potentially oscillate or assume an intermediate voltage that causes excess current draw.

[Storic]

thanks after thinking about this, you have confirmed what I thought would be OK to set, yes I will set the unused pins as an output and will properly set output to low.

It is just I found on other designs, spare pins were grounded. (these may have been spare input pins )

I guess on another note, should I need to use another pin for something, I have a number of spares that I can use without the need to try and take the ground of (if externally done)
_________________
What has been learnt if you make the same mistake?

[newguy]