How to reset the serial ports on a Mac ?

Using Arduino Installation & Troubleshooting
#1

Hello,

Sometimes after a bad transmission between the Arduino IDE (v 1.0.5/Mac) and the board the serial port seem to be blocked.

Then I have two issues:

  1. The list of serial ports is not refreshed upon board connection.
  2. The IDE won't open the serial monitor and get stuck.

I have to force quit the application and most of the time I do also have to restart my user session in MacOS.
Isn't there an easier way to reset the serial ports ?

Thank you in advance.

#2

What do you mean by "bad transmission"?

#3

I mean that the upload of the program to the Arduino was unsuccessful. But whatever the cause I'd like to find a way to free the serial ports if they are blocked. Usually I have to shut down and restart the computer.

#4

Usually just unplugging the cable works for me...
You can check if the port is available in terminal.

  1. Open terminal (Applications/utilities)
  2. Type ls -las | grep usb
  3. You should see your ports listed. If you remove the cable, the port will no longer be listed.
  4. Reinsert and you should have a new connection.

I have this issue when using three or more arduinos at the same time... Also always make use you use the correct serial port when you upload.

Hope this helps.

#5

If you're getting "serial port in use" when this occurs, it is probably because avrdude is still holding the port open.

Here's a couple of things to check if that's the error you are getting:

#6

Thanks James C4S and Kevin77.

Is it normal that the "ls -las | grep usb" command returns absolutely nothing, even with at least one busy serial port ?

#7

amundsen:
Is it normal that the "ls -las | grep usb" command returns absolutely nothing, even with at least one busy serial port ?

I'm not sure what the intent of that command was.

I'd recommend what I explained in my post:
"lsof | grep usb"
which will list all open serial ports (devices are given file handles, which is why the list of open files command works)

or

"ls -l /dev/ | grep usb"

Which will tell you if an active serial port is available.

#8