No device found on ttyACM0

Using Arduino Avrdude, stk500, Bootloader issues
1

My UNO R4 WIFI works well on Windows, but in Linux (cinamon) I'm missing a device :
"No device found on ttyACM0".
Yes, I checked, and did not find the entry with ls -l /dev/
Some say to download a firmware update, but the updater complains about that missing port too ?

2

Linux requires you to be a member of the dialout group. Try these, one should work. Not gil is my user name.
Type 'groups', is 'dialout' there ?
sudo usermod -a -G tty yourUserName - sudo usermod -a -G tty gil
sudo usermod -a -G dialout yourUserName
Log off and log on again for the changes to take effect.
The last step is most important!

included with IDE2.2.?
sudo groupadd plugdev
sudo groupadd dialout
sudo usermod -a -G tty $1
sudo usermod -a -G dialout $1
sudo usermod -a -G uucp $1
sudo usermod -a -G plugdev $1

Disconnect the board.
Run dmesg -w; the program will not close.
Connect the board and check if there is any change in the output of (2) above.
Stop dmesg -w using ctrl+C.

cd /dev
ls -l

3

Are you saying the system cannot detect a device on /dev/ttyACM0, or that /dev/ttyACM0 itself is missing?

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4

@van_der_decken I updated Linux and the /dev/ttyACM0 appeared afterward, but I still can't use it, same error!
Yes, I did reboot !

5

@gilshultz You didn't explain anything, don't just give steps, make sure you explain yourself, please !
the first line didn't give I just got : Usage: usermod [options] LOGIN as if it was wrong, without explaining, just like you !

6

Please show the results of the following commands:

  1. ls -l /dev/ttyACM0
  2. ls -l /etc/udev/rules.d
  3. groups

This is not intended to fix the problem, merely to provide more information in order to try and diagnose what is going on.

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7

1- ttyACM0 is there : crw-rw---- 1 root dialout 166, 0 Aug 27 12:55 /dev/ttyACM0
2- but : /etc/udev/rules.d~': No such file or directory
3- groups are UserName adm cdrom sudo dip plugdev lpadmin sambashare
I used UNIX in the old days when I was a student, but never as system manager. Everything was setup and ready for use. It's been 40 years so I don't understand much of what I'm doing right now.

8

You need to add your username to dialout group.
Run this as root or via sudo:

usermod -a -G dialout <username>

Then logout and log in again.

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9

After usermod -a -G dialout
I get
usermod: Permission denied.
usermod: cannot lock /etc/passwd; try again later.

10

As i wrote above,
you need a root privileges to do this.

11

Please tell me, I don't know how to do "as root" ?
I used sudo and it worked though.
Do I need to do something like close the terminal and reopen, or reboot... ?

12

If you done it already, (an it worked) what do you ask now?

exit from the profile and login again

13

I asked how do you "run as root" ?
What's a profile ? the command shell or the whole login ?

14

Type su command and then enter root's password. After that you will logged as root and will able to run commands "as root".
Once you are done, type exit and you will be back as "user"

15

Thanks, I decided for a reboot and everything is fine now, and my Arduino is working again !
So I had to get the latest updates for Linux, in order to have a device to talk to (ttyACM0), and with the "usermod -a -G dialout", all is fine, though I don't really understand much of it...
thanks a lot !

16

Please mark the topic as solved to help others with similar issues.

17

Right, that was the point of me recapitulating in the last message, will do !
Thanks for a job well done !

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