Unused pins

[mister_e]

Pull-down/Up may also be useful as test point or for future modification.

[peterdeco1]

I have had port pins actually toggle their state from high to low, inputs to outputs, outputs to inputs and disable the HPWM because of spikes generated from a small hobby motor. NO, additional power conditioning did not help as the motor was completely isolated with it's own battery supply. All the PIC did was activate a relay. However, the PIC was only 1/2 inch from the case of the motor. Seems my problems went away by making all unused ports output low & leave them floating. I also repeated the tris command repeatedly in case a spike toggels it into an input to prevent a floating input situation.

[manxman]

So it seems the average answer is YES XOR NO! Yup, if I accidentally re-assign an unused grounded pin as output and make it high then we have a problem. To be safe I'll tie all unused pins low via 10K resistors.

Thanks guys.

[mister_e]

it's not a bad idea to refresh at least TRIS register while your program is running. ... at least for safety sake.