How to Install CH340 Drivers

Contributors: bboyho, santaimpersonator
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COM Port is Not Showing Up as CH340 Windows

We have had a few reports on Windows 10 where the driver will automatically install and the board will show up under a new COM port as USB-Serial CH340, but with a different device name. However, the board cannot be accessed on the Arduino IDE. Others have had issues where the installation process hangs.

Based on the customer experiences, this might be specific to the manufacturer and are usually isolated cases. Users seem to be able to eventually get the board recognized by a combination of giving the computer time to finish the install (close to 20 min), plugging the board back in multiple times, reinstalling the drivers, and/or resetting the computer multiple times (repeat both steps).

COM Port Not Available Windows, Mac, and Linux

If you installed the drivers for the CH340 on your computer but have issues connecting via serial terminal or uploading code using the Arduino IDE, there may be an issue with your user settings preventing you from using the CH340. You may receive an avrdude: ser_open(): can't open device error similar to the output shown below.

avrdude: ser_open(): can't open device "/dev/ttyUSB0": No such file or directory

In this case, the error appeared on a Linux when trying to upload code due to the drivers not being installed and the root permissions.

Arduino ser_open() error

Make sure to check your configuration settings and ensure that the serial port for the CH340 is enabled for your OS. You may also need to reinstall the drivers for your operating system.

USB Cable Windows, Mac, and Linux

Certain USB cables are for power only and may not have the data lines available. Try checking your USB cable and ensure that the data lines are intact.

Issues Uploading at Fast Baud Rates

If you are uploading to certain boards like the Apollo3 on the Artemis development boards with fast baud rates, there are some platforms (Linux flavors) where the standard CH340 USB to serial drivers don't operate well at speeds higher than 115200. So if you run into upload problems, consider reducing the upload speed. For more information about upload issues, see this forum post and consider upgrading with these drivers for Mac OSX or these for Linux.