Install Drivers for the Simulink Coder Support Package for BBC micro:bit
- Click this link: mbed Windows serial port driver. 
- Download the mbed Windows® serial port driver on your computer. 
- Run the installer. - To complete the installation, follow the on-screen instructions. - After successful installation, you will see MICROBIT below the Portable Devices option and the serial port below the Port (COM & LPT) option of the Device Manager screen. 