3
\$\begingroup\$

I have a customer who is looking for a split Micro-USB cable, which has one USB-A host connector on one end and two Micro-USB cables on the opposite end (they will be plugging into cameras). Can I simply wire it like this diagram I've attached? I believe he has software he is experimenting with where he is trying to control two cameras simultaneously. I've seen "zipper-stlye" split Micro cables like this. Is this simply the operative wiring? Thanks in advnace, friends.

enter image description here

\$\endgroup\$

closed as off-topic by Chris Stratton, RoyC, Turbo J, laptop2d, Sparky256 Feb 11 '18 at 7:08

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Chris Stratton, RoyC, Turbo J, laptop2d, Sparky256
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 6
    \$\begingroup\$ Directly connecting two USB devices to one host port like this wouldn't work. A USB device needs to enumerate with the host. I don't know what the consequences of doing this are, but I'm pretty sure they aren't good. This is the reason USB hubs exist. \$\endgroup\$ – Daniel Feb 9 '18 at 6:29
  • 8
    \$\begingroup\$ This will not work; we had basically the same question here a few days ago. If you ignore the USB data aspect you might by some edge-case abuse of specs deliver power. But data is out of the question. USB requires a HUB for that. \$\endgroup\$ – Chris Stratton Feb 9 '18 at 6:30
  • \$\begingroup\$ What happens when USB-A as a host attempts to program the local address in for micro-USB-a, and USB-b gets the same packet? You will have packet collisions and thus no connection to either micro-USB. \$\endgroup\$ – Sparky256 Feb 11 '18 at 7:07
11
\$\begingroup\$

This does not work. You will need a USB hub.

The USB Y cables you have seen use two USB Type A male plugs to one USB B type plug. Only the power lines are split to the extra plug.
This is not conform the USB specification. But it is a small hack to have more than the standard 2.5 Watts of power available, it is used for 2.5" hard disks that can't spin-up with just one plugs worth of power.

\$\endgroup\$
  • \$\begingroup\$ Could you hide a hub inside the A plug? \$\endgroup\$ – Random832 Feb 9 '18 at 15:07
  • \$\begingroup\$ @Random832: There's no reason you couldn't CoB a die from, say, Genesys Logic in the connector. \$\endgroup\$ – Ignacio Vazquez-Abrams Feb 9 '18 at 17:42
  • \$\begingroup\$ @IgnacioVazquez-Abrams Yeah, I went looking for an example after I posted that comment. \$\endgroup\$ – Random832 Feb 9 '18 at 17:42
  • \$\begingroup\$ Yeah, I have seen commercial cables like this out there, so they must be doing something like that with a CoB. If anybody has more info about that, or instructions on how to DIY it, I'd love to hear about it. Thanks! \$\endgroup\$ – rockwell Feb 9 '18 at 17:55
0
\$\begingroup\$

If you look at these cables you mentioned - This one, claiming to be the "original", is one example, and their site does include a circuit diagram that makes it clear, you will see that either the type A connector is typically slightly larger than a normal one, or there is a small box in the middle of the cable. This is because USB hub electronics are hidden inside, rather than it being a simple plug connected directly to the wires. There's likely no particular advantage (other than space saving) over using a standard hub.

\$\endgroup\$

Not the answer you're looking for? Browse other questions tagged or ask your own question.