I want to use the USB serial port with a micro:bit and Windows.
How do I transfer data between a micro:bit and a Windows PC?
Where is the serial driver for the micro:bit for Windows?
Why doesn't the REPL work with Mu on Windows?
In Windows 10 Windows Update will fetch the mBed driver, for earlier versions. If you have used mBed before and upgraded, you may need to re-install the driver.
Once you have installed this driver, the micro:bit will also appear in device-manager as a COM port, and you can use any terminal program like Hyperterminal to send and receive data to and from the micro:bit over the USB serial lead, using the 'serial' language capabilities of many of our standard coding languages.
You should also set the baud rate to 115200.
Note that when installing the Windows mbed driver, you should make sure that the micro:bit is plugged into the USB first, before trying to install the driver - some users have experienced 'unknown install errors' of this driver, and it seems to be related to not having the micro:bit actually plugged in at the time you do the install. You will also need full admin rights on your PC to install the driver.