https://devzone.nordicsemi.com/f/nordic-q-a/50112/can-nrf52840-p0-09-p0-10-be-used-for-115-kbps-uart-outputWhen nRF52840 P0.09 / P0.10 are used as GPIOs, the datasheet indicates they can be used for &quot;low frequency I/O only&quot;. What is the frequency limit on these pins? Would it be possible to use them to drive 115 kbps UART output?en-USTelligent Community 13Tue, 23 Jul 2019 07:00:04 GMThttps://devzone.nordicsemi.com/thread/199926?ContentTypeID=1Tue, 23 Jul 2019 07:00:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7a34d603-ff5e-4042-bb1b-e7f13f79b5e6Simonr<p>Hi Nathan</p> <p>P0.09 and P0.10 are by default NFC pins in the nRF52840, but you can configure them to be GPIOs by following<a href="https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fpin.html&amp;cp=3_1_0_3_2_1&amp;anchor=concept_sq5_lcz_2q"> these instructions</a>.</p> <p>When using these pins as normal GPIOs they are limited to a lower frequency than other GPIOs, as the loading is somewhat different on NFC pins than regular GPIOs. &quot;Low frequency I/O only&quot; means that the pins shouldn&#39;t be used for frequencies above 10kHz. So you&#39;ll have to use other pins for &gt;10kHz operations.</p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>