https://devzone.nordicsemi.com/f/nordic-q-a/53634/external-pull-up-down-needed-on-spi-nrf52840-package-wlcspHi, I use in my design a component which use the nRF52840 - WLCSP package. I use SPI to connect the nRF to a SD card slot. With the package, I understand that pin K4 (P0.19) is for SPI_SCK and for 3 others signals I can use pin J4 ( P0.21), K3 (P0.22en-USTelligent Community 13Fri, 25 Oct 2019 14:26:20 GMThttps://devzone.nordicsemi.com/thread/216896?ContentTypeID=1Fri, 25 Oct 2019 14:26:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ef4e641f-41f5-4c07-b07b-8daa1bf214d9E. Chevalier<p>Thanks Jared!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/216835?ContentTypeID=1Fri, 25 Oct 2019 12:27:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7bd7d1d0-ec1a-460d-a04b-e7bca4d7b504Jared<p>Hi,</p> <p>External pull up isn&#39;t needed except if the internal pull up of 13k ohm isn&#39;t strong enough for you application. In most applications 13k ohm is enough.</p> <p>regards</p> <p>Jared</p><div style="clear:both;"></div>