Support for stdin/stdout over USB serial (CDC) .

Linking this library or calling pico_enable_stdio_usb(TARGET ENABLED) in the CMake (which achieves the same thing) will add USB CDC to the drivers used for standard input/output

Note this library is a developer convenience. It is not applicable in all cases; for one it takes full control of the USB device precluding your use of the USB in device or host mode. For this reason, this library will automatically disengage if you try to using it alongside tinyusb_device or tinyusb_host. It also takes control of a lower level IRQ and sets up a periodic background task.

This library also includes (by default) functionality to enable the RP2040 to be reset over the USB interface.