Unused GPIO Pins

RE: Unused GPIO Pins

Håkon Alseth — Tue, 22 Aug 2017 10:14:05 GMT

No worries. That is normal when configured in this GPIO-disconnect mode.

RE: Unused GPIO Pins

annapalu — Tue, 22 Aug 2017 09:11:22 GMT

Hi Hakon,

i have set the internal switch of unsed pin to 1 ( disconnect). But if i measure the the voltage on the pin, for some of them is 3 V for the other 0. is it normal?

Thanks.

RE: Unused GPIO Pins

sort — Mon, 12 Sep 2016 06:20:57 GMT

Hi, Alseth,

I am very concerned about ESD ( 8KV/15KV for contact/air respectivelly) in my project. For the unused GPIO pins, do I need to add TVS diode or pull-resistor to the GND?

RE: Unused GPIO Pins

Håkon Alseth — Tue, 05 Aug 2014 11:41:58 GMT

Yes, that is correct.

RE: Unused GPIO Pins

Imran — Mon, 04 Aug 2014 14:16:39 GMT

So the pin is kept floating on the PCB but the internal switch is disconnected?

RE: Unused GPIO Pins

Håkon Alseth — Mon, 04 Aug 2014 12:43:48 GMT

Hi Imran,

The default behavior of unused GPIOs (it's reset value) is set as input, with an internal switch (NRF_GPIO->PIN_CNF[], bit 1) set to disconnect. This is the recommended configuration of unused GPIOs to ensure that they do not draw current due to floating inputs.

So, just keep the unused pins un-connected on your custom PCB and make sure that these pins have the reset value of NRF_GPIO->PIN_CNF[].

Cheers, Håkon