I've been working on a DMX project for my Arduino Duemilanove which communicates over USB. I'm having problems with using a longer USB cable though...
With the short usb cable (1.5 ft) that came with my Arduino, everything works fine. Windows recognizes the device as the arduino and I can program it, send dmx signals, etc. to it just fine.
However, when I use a longer USB cable, when I plug it in, Windows shows a popup that says "USB Device Not Recognized". I've tried it with a 10 ft cable (working cable from my printer) and a 15 ft cable (brand new and the one I'd like to use for my project).
In Windows Device Manager, when I plug it in using the long cables, it recognizes some sort of USB device but it is like it isn't communicating all the way with it. Specifically, Device Manager says "device descriptor request failed" next to it.
I tried plugging the arduino into its own power supply before plugging the usb cable in in case it made a difference but the same thing still happens.
Does anyone have any suggestions on what else I can try? What might be going on here?
I have a powered usb hub. If I connect my laptop to the usb hub and then plug the long cable into usb hub, everything works fine... So I'm guessing it has something to do with the 'powered' aspect of the usb hub?
Anyone have any additional thoughts?
I guess as a workaround I can use my usb hub... thats somewhat inconvenient though...
This is an ancient thread I know, but it is the only one I found pertaining to my issue. I have a knockoff arduino 2650 with a CH340G chip instead of the atmel one, and found that even just the voltage drop of an 8ft cable was enough to cause a device descriptor error. Connecting the same 8ft cable to a powered usb hub solved the issue.
I think the CH340 is just a poorly designed chip. It is supposed to have a VCC range of 4.5 to 5.5 volts in 5v mode, but 5.03 volts from my PC would not work. The powered hub increased that to 5.1
I'm not sure about the OP's issue, but in my case it's just a matter of bad design. all my genuine boards work fine on that same cable or even longer. Just another reason to always buy genuine in my case.