Spurious input signals on switch

Official Hardware Mega Due
1

Hi

Got my first Due yesterday - I have tried both the internal resistor and pull up / pull down external 10k resistor. I get an occasional read when the switch is open (but both internal and one of the 10k methods are quite bad - the other 10k method seemed to be working a lot better but also not 100%).

On a Uno it is rock solid with the same cable.

Any ideas?

I have 3.3v going to 10k, 10k going to pin 12 and gnd.

Thanks
Garth

2

Seems to have been noise - perhaps the cable was lying too close to the stepper driver. It works fine with the internal resistor if tried standalone