USB Cable

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USB Cable

Postby DanB » Sun Feb 27, 2011 6:17 pm

Hi all,

The nearest USB socket I have when using my computer is at the front of the unit. Unfortunately this is located at (or near to) floor level in a computer desk unit. This means that the cable supplied with the XC-1A is not long enough to comfortable reach the keyboard area... Indeed on one occasion I tried this but (it may because I had the retractable cable at full length) it decided to retract, dragging the development board to the floor. Although not a great distance to the floor (about 0.75m at a guess) it must have hit the (carpetted) floor at a bad angle as the surface mount USB socket seperated from the board. Fortunately it came cleanly off and I was able to re-solder it... When tested it appears everything is fine after that incident, though I've not dared to use XC-1A with the included cable since as it is clearly a little risky, with the combination of its length being a little short for my needs and the concern that it may retract again in future.

Suprisingly I have no other suitable USB cables with a length suitable to have the XMOS on the worksurface. This meant that I was (and am) unable to use the XC-1A at present.

To rectify this I ordered a 2m USB extension cable, with the idea that I could leave that perminantly plugged in, giving me a USB socket at desk level - Convinent for the XC-1A and any other USB devices.

This cable arrived however with the extension cable in the USB socket on the front of the PC case, and the retracted able (fully wound) plugged between the extension and the XC-1A the development kit does not connect manage to connect to the computer (I constantly get the USB plugged in and unplugged sounds alternating). With this in mind I quickly tried another mini USB cable (about 20cm in length - so a direct connection between the PC and XC-1A) however this has the same issue (USB pluggin in and unplugged sounds alternating).

I've verified that both the cables used work: I've tried the USB extension with a pen disk just fine. I've tried the (short) mini USB cable with an MP3 player which also worked fine.

This leads me to believe that the XC-1A only works with the included cable (which sadly is not suited to my needs). Is this a known issue? Or is the XC-1A somehow damaged/faulty? I've got a gender converter (see here: ... 0534646076) coming so that I can use the XC-1A directly, pretty much, connected to the computer, but with the more useful length of 2m. My guess, however, is that this will fail to work (considering I've had no success with other cable combinations).

Any advice?

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Postby leon_heller » Sun Feb 27, 2011 6:27 pm

You probably need a cable rated for High-Speed USB 2.0.
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Postby DanB » Sun Feb 27, 2011 6:43 pm

leon_heller wrote:You probably need a cable rated for High-Speed USB 2.0.
I doubt the short mini USB cable I used it rated for USB 2.0 so that's an interesting idea. Having said that the 2m USB extension cable is rated for USB 2.0 and that was used in conjunction with the included XC-1A USB cable so I'd have thought that would be okay (save for the combined length...).
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Postby Berni » Sun Feb 27, 2011 8:18 pm

It might be a voltage drop problem, this often happens when you use a too long cable on a power hungry USB device. If you have a 5V wall wart handy you can try powering the board from that (Do measure it first since you can never trust wallwarts)

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