https://devzone.nordicsemi.com/f/nordic-q-a/57698/pca10040-virtual-com-port-what-is-it-used-forHi We are using PCA10040 for a development and we are using P0.8 , we were setting it up to be No connect when low (IE Open collector) but it was being driven high and we realized it was used for the virtual com port as described in the PCA10040 useren-USTelligent Community 13Wed, 12 Feb 2020 09:35:18 GMThttps://devzone.nordicsemi.com/thread/233906?ContentTypeID=1Wed, 12 Feb 2020 09:35:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f29d55a3-7a09-401b-acb5-5ecd2ac58946awneil[quote userid="77447" url="~/f/nordic-q-a/57698/pca10040-virtual-com-port-what-is-it-used-for"]We were expecting this to have some affect on the debugging interface[/quote] <p>Why would you expect that?</p> <p>Debugging used the <strong>SWI</strong> interface - as for <em>any</em> Cortex-M microcontroller.</p> [quote userid="77447" url="~/f/nordic-q-a/57698/pca10040-virtual-com-port-what-is-it-used-for"]or logging[/quote] <p>Logging can be configured to use Segger RTT, or the UART.</p> <p>To use the UART, you need&nbsp;a COM port.</p> <p>RTT uses the debug interface.</p> [quote userid="77447" url="~/f/nordic-q-a/57698/pca10040-virtual-com-port-what-is-it-used-for"]So what is this com port used for ?[/quote] <p>It connects the UART of the nRF52 chip to a virtual COM port on the development Host (eg, PC) - so that you can do serial comms between host &amp; target.</p> <p>eg, send text to a terminal and/or receive text from a terminal.</p><div style="clear:both;"></div>