Why doesn't Zaber device show up in dev directory?

Question

My Zaber device is X-MCB2, which is connected to my computer through USB. Command lsusb can show its information as below, but cannot find it in /dev directory.

Bus 003 Device 023: ID 2939:495b

There is another Arduino device connected to my computer as well. Unlike Zaber device, this Arduino device works well, its name in /dev is ttyACM0.

Even if I plugged out the Arduino device, the Zaber device still does NOT show up in /dev directory.

My linux kernel is 2.6.32, and this Zaber device shouldn't need additional driver.

Answer 1

I resolved this issue according to the following link: https://github.com/arduino/Arduino/issues/1389.

echo "0x2939 0x495b" > /sys/bus/usb/drivers/cdc_acm/new_id

Answer 2

Thanks for posting your answer Jeff.

The likely cause of the issue is that Zaber controllers implement USB using CDC ACM, and set 0 for the Protocol field of the USB interface descriptor (indicating that the device doesn't accept AT commands).

In Linux 2.6.32, the CDC ACM kernel driver, which should handle devices of this type, is written in such a way that it doesn’t take control of devices whose Protocol field is 0 (instead it has a specific list of Protocol numbers which it accepts, but that list does not include 0). Instead, you must manually attach it as in the posted solution.

This issue was fixed in kernel 2.6.36.

Here are a list of the commands that will manually attach the Zaber controllers with USB:

X-MCB2:

echo "0x2939 0x495b" > /sys/bus/usb/drivers/cdc_acm/new_id

X-MCB1:

echo "0x2939 0x495a" > /sys/bus/usb/drivers/cdc_acm/new_id

A-MCB2:

echo "0x2939 0x459" > /sys/bus/usb/drivers/cdc_acm/new_id