4 ms·
That was a fun read. Interesting trick with the debug USB cable with some of the pins isolated.
by therein 8y ago
That was a fun read. Interesting trick with the debug USB cable with some of the pins isolated.
- rzzzt 8y agoI don't quite get how it works. A quick search tells me that USB 3.0 indeed allows A-A crossover cables to connect two hosts: https://superuser.com/a/945523 https://superuser.com/a/945523 ...but this leaves only a single conductor to do the entire thing?
- AnssiH 8y agoA USB3 A connector has 9 pins, not 4 like USB2, so there are still 6 left.
- snops 8y agoAnd those 6 pins are separate TX and RX pairs, and 2 grounds. The pins disconnected are 5V, which would potentially damage things or cause an overcurrent flag to trip (turning off both ports) if this was connected on both ends, and D+/D-, which is the bidirectional USB2.0 data pair that normally has fixed host/device roles and needs a special controller (like the one in your phone) to be dual role, so it's easier to just disconnect it. The USB3.0 TX/RX pairs are only one way each (think like RS232 null modem but much faster), so it's much easier. This is a good example of how USB3.0 works almost like a separate, parallel bus to USB2.0.
- tyingq 8y agoThe picture is somewhat misleading, as you can only see the 4 connectors in the front. The other 5 are out of view. https://www.stemmer-imaging.com/media/cache/gallery_preview_505/uploads/acquisition/sis/gl/glossary-USB3-2-en.JPG https://www.stemmer-imaging.com/media/cache/gallery_preview_...
- superkuh 8y agoThere's the other side plus the shield itself is a pin. It's the ground.