I have a USB 3 to sata connector which I know worked on my Raspberry Pi 3 (USB 2). I have now cut the USB 3 cable and wanted to solder the wires directly to the Raspberry Pi. This is so that I can power the HDD and the Pi from the same power source (without using a powered USB hub).

I am getting no response when I power the Pi with the soldered HDD. I connected the 4 USB wires to a normal USB cable and plugged it in my laptop. It is not even detected.

lsusb and dmesg show no signs of the device being detected.

So my question is, are there any other requirements to get a USB 3 to be backwards compatible? I thought it would just be a case of not connecting the SuperSpeed data pairs and only using the normal USB 2 data pair.

I also have left the shielding unconnected. Since there should not be any disturbances around and the wire is short, I would assume this is fine.

  • \$\begingroup\$ Just to be clear: your did solder wires to Pi3, and then plugged the other and of USB cable into your laptop, right? How do you expect this to work, if Pi3 is a host, and laptop is a host? \$\endgroup\$ – Ale..chenski Apr 29 '17 at 22:12
  • \$\begingroup\$ Use a multimeter to probe all of the USB wires. What does it say? \$\endgroup\$ – ArchHaskeller Apr 29 '17 at 23:50
  • \$\begingroup\$ So soldered the HDD USB to the Pi and them it didn't work. I desoldered it and then attached the USB wires to a normal USB male plug. Leaving the USB 3 Super speed pairs unconnected. I plugged the USB male into my laptop. There was no host to host connection. \$\endgroup\$ – Brandon Apr 30 '17 at 6:55
  • \$\begingroup\$ @ArchHaskeller VCC = 4.92 V; D+ = 2.75 V; D- = 2.75 V; SSD+ and SSD- = +-0.2 V \$\endgroup\$ – Brandon Apr 30 '17 at 6:57

I am answering this question myself as I found the issue. When I heat shrinked the cables, I applied too much heat for the thin USB wires. This fused the USB D+ and D- wires.
So the actual answer to my question is no you do not need to do anything else with the USB 3 SuperSpeed data pairs, you should just leave them unconnected.

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