https://devzone.nordicsemi.com/f/nordic-q-a/39445/nrf52840-dongle---why-are-p0-19-21-23-25-tied-to-p0-18-resetThe subject really says it all; why are there four GPIOs tied to P0.18 which is the nRF52840&#39;s RESET# pin? I&#39;m looking at the PCA10059 Schematic available in the nRF52840 USB Dongle - Hardware Files 1.0.0 zip file.en-USTelligent Community 13Mon, 15 Oct 2018 00:48:03 GMThttps://devzone.nordicsemi.com/thread/152779?ContentTypeID=1Mon, 15 Oct 2018 00:48:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ea79c7f4-7bf4-4d50-858f-970ab4b4ed59RK<p>From the documentation</p> <p></p> <p>1 SW2 is also connected to P0.19, P0.21, P0.23, and P0.25. This is done to simplify PCB routing. These GPIOs should not be used and should be left as input with no pull or be disconnected by firmware.</p><div style="clear:both;"></div>