USBSerial on f446re

Hello,

that is obsolate, the latest you can found here - USBSerial - API references and tutorials | Mbed OS 6 Documentation

In addition you also need to place the content below to the mbed_app.json file

{
    "config": {
        "usb_speed": {
            "help": "USE_USB_OTG_FS or USE_USB_OTG_HS or USE_USB_HS_IN_FS",
            "value": "USE_USB_OTG_FS"
        }
    },
    "target_overrides": {
        "*": {
            "target.device_has_add": ["USBDEVICE"]
        }
    }
}

The PC application also need to manage the DTR signal .

BR, Jan