I'm using ubuntu 16.04. The ubuntu system responces well to a direct connection via usb with Arduino Leonardo and an another Mega board. The Leonardo is the microconroller MEGA32U4, is not a real arduino board.
I use an interface with power supplies for the motors. When the connection is through that interface the ubuntu greys out the port. Only the ttyS0 is shown. (I am looking for something like ttyACM0.)
What comfusing is the connection of usb + interface + arduino is successful connected to my windows 7 PC.
I am wondering is there something missing or wrong with the Ubuntu system, which make it be able to run Mega and Leonardo with direct usb connection but fail with interface?
When I run "sudo modprobe fdti-sio" this morning, the connection with interface between the leonardo and the ubuntu established for a brief moment, I could open the serial monitor to send message and get response from leonardo. But the connection lost and cannot be restored after I unpluged and pluged the USB.
Here is what lsusb shows with a Leonardo plugged in.
$ lsusb
...
... ID 2341:8036 Arduino SA Leonardo (CDC ACM, HID)
...
Here is what dmesg shows.
$ dmesg
usb 2-2.1: new full-speed USB device number 12 using ehci-pci
usb 2-2.1: New USB device found, idVendor=2341, idProduct=8036
usb 2-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-2.1: Product: Arduino Leonardo
usb 2-2.1: Manufacturer: Arduino LLC
cdc_acm 2-2.1:1.0: This device cannot do calls on its own. It is not a modem.
cdc_acm 2-2.1:1.0: ttyACM2: USB ACM device
Things to try
Different USB cables.
Different USB ports.
USB 2.0 hub. Some boards do not work with USB 3.0 ports.
Thanks gdsports for your advice.
Im pretty sure I m using a good port and cable. I tried the both command of lsusb and dmesg, but there is any change before and after the usb plugs in.
The microcontroller with Leonardo can be detected without interface. But failed with that interface .
I do think the usb hub may help.
And I will read the link you geve me.