It is not necessary to use USB with a Duet board for normal operation however there are a number of troubleshooting instructions that require connecting to the Duet over USB (normally when connecting over the network is not working for some reason).
Different operating systems have different terminal emulator support built in. In windows it is necessary to instal a terminal emulator. Most Linux distributions have one built in, however a program with a GUI like CuteCom may make using it easier for people who prefer GUIs. CuteCom should also work on MacOS, other people may prefer SerialTools.
There are many terminal emulators available for windows, the simplest and most reliable we have found is Yet Another Terminal (YAT). You can install it from Sourceforge here
With its standard setup the line endings are not set correctly for Duet. This page shows how to set the line endings correctly.
There are different standards for how to end a line - see Wikipedia for more information. Setting them wrong in a terminal emulation program leads to a long single line (which may be too long for the terminal):
Setting them right gets the response you would expect:
The Duet uses <LF> for line endings (Unix like). To set them in YAT go to Terminal in the top menu bar then Settings:
Any content here will go into the first tab...
Then select Text Settings and change the EOL sequence selection to <LF>
Unless you have other serial devices connected to your machine, other than the Duet, there will probably only be one COM port available for selection in YAT:
Select the available port under Serial Port, the defaults for Bits per second etc should work.
Then click the green tick to connect (or Terminal menu then Open/Start).
If the COM post is not available that is outside the scope of these instructions, check your USB connections, try a different cable and port, see Installing and Updating Firmware - Fallback procedure Num 2
For macOS, we recommend using SerialTools from the AppStore.
Install SerialTools and run it. Select the Duet from the 'Serial Port' drop down; it will be named something like "usbmodem1411". Baud rate should be 115200, and Local Echo should be ticked. Click 'Connect' to connect.
It is also possible to use the built-in 'screen' terminal application. However, you cannot see the commands you type in, and the responses from the Duet are not formatted nicely on the screen.
If you want to use 'screen', open Applications > Utilities > Terminal. Run
screen /dev/tty.usbmodem1411 115200, replacing "usbmodem1411" with the Serial Port name for your Mac, if different.
Hit enter and you should see OK returned. You are connected successfully.
If you get an error, "Sorry, could not find a PTY." unplug the USB, plug it back in and try again.
To exit 'screen', press CTRL-A then CTRL-\ to exit screen and return to terminal.
There are many options to connect using Linux. Our favourite is to use CuteCom, which is a GUI serial terminal. Cutecom is also available for macOS.
It's available in most package repositories, or install with
sudo apt install cutecom. It can also be downloaded from here. It should automatically detect the correct port (usually /dev/ttyACM0), and is configured correctly out of the box. Click 'Open' to connect.
Alternatively, you can use a text-based serial terminal application such as Minicom. Install with
sudo apt install minicom, and run from a Terminal window with
minicom -s, which starts it in setup mode. Select 'Serial port setup', then 'A', and change the port to '/dev/ttyACM0' (or the port name from step 2). Press return twice, then 'Exit'. The terminal will start.
Press CTRL-A then W for linewrap, CTRL-A then U for CR at end of line, and CTRL-A then E for local echo. CTRL-A then X quits Minicom, releasing the port.
Finally, you can use the built-in 'screen' terminal. However, you cannot see the commands you type in, and the responses from the Duet are not formatted nicely on the screen. If you want to use 'screen', do this:
screen /dev/ttyACM0 115200. (Replace "ttyACM0" with the port name if it's different.) Hit enter and you should see OK returned. You are connected successfully.
To exit 'screen': CTRL-A then \ to exit screen and return to terminal.