The CH340 chip is used by a number of Arduino compatible boards to provide USB connectivity, you may need to install a driver, don’t panic, it’s easier than falling off a log, and much less painful.

CH340 is a USB bus convert chip and it can realize USB convert to serial interface, USB convert to IrDA infrared or USB convert to printer interface. In serial interface mode, CH340 supplies common MODEM liaison signal, used to enlarge asynchronous serial interface of computer or upgrade the common serial device to USB bus directly.

Windows

(Manufacturer’s Chinese Info Link)

1. Download the Windows CH340 Driver
2. Unzip the file
3. Run the installer which you unzipped
4. In the Arduino IDE when the CH340 is connected you will see a COM Port in the Tools > Serial Port menu, the COM number for your device may vary depending on your system.
   

Older Windows Driver Version and Instructions

1. Download the Windows CH340 Driver
   
2. Unzip the folder.
   
3. If you are running a 64Bit Windows: – run the SETUP_64.EXE installer.
   
4. If you are running a 32Bit Windows: – run the SETUP_32.EXE installer.
   
5. If you don’t know, try the 64 bit and if it doesn’t work, the 32 bit.
   
6. In the Arduino IDE when the CH340 is connected you will see a COM Port in the Tools > Serial Port menu, the COM number for your device may vary depending on your system.
   

Macintosh

(Manufacturer’s Chinese Info Link)

(V1.3) Download the CH340 Macintosh Signed Driver for Mavericks (10.9), Yosemite (10.10) and El Capitan (10.11) and Sierra (10.12)

Inside the zip file you will find a PDF and a “pkg” file, short version, double click the pkg file, the PDF has some extra information.

OSX Sierra (10.12) Note

A kindly user, Maarten Segers reports

FYI, the driver documented here WILL crash on OSX Sierra.

I can personally not test on MacOS and can not vouch for the above drivers at github, but there you go.

See uninstalling information at the bottom of the page if the driver causes problems for you.

Here is an older version of the Mac driver, NOT FOR 10.12 Sierra

(V1.0) Download the CH340 Macintosh Signed Driver for Mavericks (10.9), Yosemite (10.10) and El Capitan (10.11)

Linux

(Manufacturer’s Chinese Info Link)

Drivers are almost certainly built into your Linux kernel already and it will probably just work as soon as you plug it in. If not you can download the Linux CH340 Driver (but I’d recommend just upgrading your Linux install so that you get the “built in” one).

Uninstalling From Macinstosh

Usb Ch340 Serial Rs232 Config

A couple of Mac users have said “the driver crashes my mac Sierra how do I uninstall”.

Firstly regards the crash make sure you installed the 1.3 version of the driver, not the old one. You could download it directly from the Manufacturers Website in case they have issued an update since I wrote this page.

Secondly a quick google search reveals that this is how you uninstall:

Usb Serial Ch340 Vag Com

1. Open a terminal and type: cd /Library/Extensions/
2. Verify that the .kext file is present: ls | grep usbserial.kext
3. Output should be: usbserial.kext
4. Then type: sudo rm -R usbserial.kext
5. Verify that the .kext file has been removed: ls | grep usbserial.kext
6. Output should be empty.
7. After you should remove the files stored in receipts folder: cd /private/var/db/receipts/
8. Find the enties: ls | grep usbserial*
9. Output should be: codebender.cc.ch34xinstaller.usbserial.pkg.bom codebender.cc.ch34xinstaller.usbserial.pkg.plist
10. Remove each one of the files of the above list: sudo rm -r filename`