I'm tryin to get the USB CDC ACM Sample Application to work on my nRF52840DK board (https://docs.zephyrproject.org/2.6.0/samples/subsys/usb/cdc_acm/README.html).
I've followed the steps exactly but it's stuck at "Wait for DTR". Is this application meant to work with a USB cable only or do I need to an FTDI chip?