Serialusb.println hangs after disconnecting USB cable

Not something which would happen regular but I would like to understand why this happens and more important how to resolve it. I have an autonomo with a battery attached and connected thru USB. The USB port is used to write debug messages. I detach the USB cables and all runs fine untill I sent the a message to the USB port, SerialUSB.println keeps waiting untill I re-connect a terminal again. This behaviour doesn’t show when I power-up the autonomo without an USB terminal attached. I don’t think this is isolated to the autonomo. Anyone any clues, before I dive into to the source code.

I recommend skylet usb cable. It really work well and you can use it for a long time.

I can only say that I don’t like using USB for debug messages. You’re much better off using one of the “real” serials.

SerialUSB has another disadvantage. The host has to reopen the device when the board gets reset. That is truly annoying if you have, or minicom or whatever connected. On Linux if you had /dev/ttyACM0, after a reset it becomes /dev/ttyACM1.

To use Serial you need some kind of USB-serial, like UartSBee. I’ve got a few of these cheap cables with built-in USB-serial. Purely for debugging / diagnostics.

OK looks as though the serial debug connector on the Autonomo is a 10 pin male and I’m not sure if a USB-UART cable with this is available off the shelf - any details please? Or do I need a USB-UART to Grove to use one of the other serials? Or is USB-UART to female jumpers the way to go and just connect to the appropriate pins on the Grove on the shield?

I’ve answered my own question. I was at the local parts shop today and picked up a USB to Serial adaptor Module (Duinotech, uses FT232). Connected this to Serial2 using female jumper to Grove that I had. Getting output using Putty (now that I’ve swapped Tx and Rx).

i’m using sodaq explorer and having the same issue.
Using serialUSB for debbuging, and after disconect and reconect, the cable, i close and re-open the serial port in the device administrator in windows, but data exchanges stop working between sodaq and terminal application on windows.

Can someone help me with this issue.

There are some work around to correct the issue? May be some software trick?

Only powering off and on the board again, the connection is restored.

Thanks in advance.


Hi @GiroSinTornillo,

After reconnecting the cable, closing and re-opening the serial-monitor should restart showing data on your screen.

I recommend to use Serial for debugging if you want to connect/disconnect the cable.

Best regards,