P1 Unused Pins on PCB, How to handle?

I am using a P1 and have some unused pins. Should all the below pins be tied directly to ground? Are there any special commands that I needs to call as pin inputs too?

These would be pins: 7-12, 14, 16-20, 33, 56-58, 60


I think all the GPIO are initialized to input during boot-up but you can explicitly set them in setup()

@kennethlimcp, thanks, I was also looking to determine if I need hard wire the unused pins to ground too to limit EMF and noise issues in helping pass FCC verification. @AndyW is this something I should do? I’m fairly confident that this should be done, but just looking for a confirmation.


Leave them unconnected, then configure them as outputs in your software.

That is the best route to take.

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@AndyW, thanks! Glad I asked.

I have a PCB that is designed as a universal with all pins connected to the connectors. It’s about a system based on Electron.
How should initialize the pins that do not use in the application.
How is it better?

  • Set as an output, and driven low
  • Set as an input, with internal pullups / pulldowns.

For the first solution of this link is written this:
“This is the worst case scenario for EMI, because each pin forms a tiny stub of an antenna.”