Electronics USB Wiring Question

Discussion in 'Offtopic Discussions' started by pmprog, Nov 27, 2018.

  1. pmprog

    pmprog Advanced Member

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    I'm sure somebody on here might be able to help. It should be simple, but I'm not sure I can get me head around it.

    I bought two USB-A panel extension cables to go in my Amiga600 case, which is populated with a Raspberry Pi, but the cables are quite thick and long, so I can't seat them nicely inside the case.

    As an alternative, I thought about using pre-made cables, the most common is USB to microUSB; so I bought some breakout boards that I can solder and 3D print a base for that can be secured in the Amiga case using hot glue.

    https://snag.gy/3xmXYp.jpg

    So as I'm only trying to pass the USB-A from my breakout to the Raspberry Pi, do I need a cross-over of D+ and D- between breakouts? or does the D+ line need to stay straight through
     
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  2. spud42

    spud42 Very Active Member

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    pretty sure they have to be straight through. D+ and D- are a differential pair. D+ needs to be D+ all the way through.
     
  3. pmprog

    pmprog Advanced Member

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    Thanks. Once I've wired it up, I'll probably test with an old mouse on a pi zero so if anything blows it's nothing expensive or important
     
  4. Grench

    Grench Forum Addict!

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    Or maybe get yourself a USB tester? I think I got mine for something like $16.
     
  5. pmprog

    pmprog Advanced Member

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    Old mouse is effectively free anda pi zero is £4... Plus i have all of them in the house without the need to order anything :)
     
  6. levi

    levi Still fresh, damnit!

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    These diagrams agree with you all. The pins are reversed because you effectivly have to rotate them about a vertical axis to orient them for insertion, but within that reversal D+ and D- are not twisted (even though they may be inside the cable, I assume).
    https://www.hobbytronics.co.uk/usb-connector-pinout
     
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  7. pmprog

    pmprog Advanced Member

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    Yep, D+ matches to D+ and everything worked fine :)
     
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