Windows serial configuration

mbed OS 2 and mbed OS 5

This is the handbook for mbed OS 2. If you’re working with mbed OS 5, please see the new handbook and API References. For the latest information about Serial, please see The Windows Serial Driver.

The mbed serial port works by default on Mac and Linux, but Windows needs a driver. These instructions explain how to setup the mbed Microcontroller to use the USB serial port on Windows.

1. Download the mbed Windows serial port driver

Download the installer to your PC, e.g. your desktop.

Download latest driver

2. Run the installer

With your mbed plugged in, and no explorer drive windows open, run the installer:

It will take some time (especially on Vista), and pop up a few 'unsigned driver' warnings, but after a while you should have a Serial port.

Where Next


If you have multiple mbed microcontrollers, but the serial port only appears for one of them:

  • Make sure you run the installer for every mbed; windows loads the driver based on the serial number, so it needs to be run for each mbed you use

If the installer fails because "No mbed Microcontrollers were found":

  • Check your mbed Microcontroller is plugged in

If the installer reports the message "mbedWinSerial_nnnnn.exe is not a valid Win32 application":

  • It is likely you are using Internet Explorer to download the installer file, which sometimes seems to only download part of the installer application for an unknown reason
  • To solve this, download the installer with a different browser (Firefox, Chrome), and try again; this should solve the issue.

If the Installer appears to hang:

  • Check if windows has popped-up a "unsigned driver/permission" window; these often get hidden behind other windows with nothing to indicate so in the taskbar! Windows may be waiting for you to click "OK"!

If you have any problems, or think this tutorial could be improved, please tell us in the Forum!