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[on:]

Hi
    I just bought an Arduino Uno and I was trying to play with it under Ubuntu, when the following problem appeared.

When I plug my arduino on my computer with the USB, I get in dmesg:

Code:

[15198.924211] usb 3-1: new full-speed USB device number 14 using xhci_hcd
[15199.001083] usb 3-1: ep 0x82 - rounding interval to 1024 microframes, ep desc says 2040 microframes
[15199.002852] cdc_acm 3-1:1.0: ttyACM3: USB ACM device

So I start the IDE, found that ttyACM3 is there, and try to upload something on my board.It says that ttyACM3 could not be found anymore and asks me to select other ports, which of course didn't work.

So I get back to dmesg and get:

Code:

[15279.574649] xhci_hcd 0000:04:00.0: ERROR no room on ep ring
[15279.574655] cdc_acm 3-1:1.1: acm_submit_read_urb - usb_submit_urb failed: -12
[15279.574659] tty_port_close_start: tty->count = 1 port count = 0.

and in fact /dev/ttyACM3 disappeared.

Any hints? On windows it works fine, but I'd like to use Linux since I do everything else there.

Thanks

[Reply #1 on:]

I'm using Ubuntu, and I found if I unplug, and then reconnect the usb cable from the computer too fast, the ttyACM number increases. So it appears to me from my experience, you have unplugged and replugged it too fast three times(?). Try unplugging it for a minute, then plug it in again.

You can check the /dev/ directory and see what shows up there when you plug in the Arduino. It should add one port, like /dev/ttyACM0

[Reply #2 on:]

Well, this happens even If i plug it for the first time. At tny moment on my system I have ttyACM{0,1,2}, so when I plug in arduino it goes to the first available port I guess.

[Reply #3 on:]

Well, this happens even If i plug it for the first time. At tny moment on my system I have ttyACM{0,1,2}, so when I plug in arduino it goes to the first available port I guess.

So this is the 4th Arduino connected to usb ports on this computer at one time? That is what that is saying. Those ttyACM0-2 devices should disappear within a minute of unplugging it.

[Reply #4 on:]

No it's the only arduino connected there, those devices should be something else.

[Reply #5 on:]

Those could be, if you have other usb devices connected. Smartphones and stuff use those. I have only my Arduino showing as ttyACM, and it is always ttyACM0.

Does the Arduino show up in the /dev/ directory when you unplug it for a while, then plug it in? Does anything disappear? Is anything added?

[Reply #6 on:]

Yes, if I unplug it and re-plug it after a while it shows up as /dev/ttyACM3, and everything goes as before.

[Reply #7 on:]

I know this sounds strange, but do you have a "!!!" somewhere in your code? That is three in a row.

[Reply #8 on:]

No, It happens with every code, even with the smallest one.