Hello, I'm working on a project where I have an M.2 device Key B that needs to use the USB and PCIE interface. I know that USB is supported on a B Key configuration but did not realize that the Udoo X86 Ultra board is only wired for SATA and PCIE. Since the M.2 USB interface uses USB 2.0 I know there is only one bidirectional differential pair, these transmissions occur on CN20 pins 7 and 9 from my M.2 card. I'm wondering if it would it be possible to make these connections through the USB 2.0 interface on the Bricks Connector, CN24 pins 3 and 4. What additional issues do you think I may run into? Any other ideas and thoughts would be appreciated, thanks!
Ahh you are correct, I've never worked with I2C before but is there anyway to repurpose these ports for my use? Do you have any other suggestions on how I could expose the USB interface from the M.2 slot?
You can solder a pair of jumper wires from an existing USB2.0 port's D+ and D- lines to the corresponding M.2 socket B connector. Need to have a great soldering skill first.
I cut an old USB2.0 cable and I was able to wire on the D+/D- lines to the M.2 interface but my USB connection failed to enumerate. Both my ground and Vbus wires are floating, I'm beginning to think that not connecting the common ground could be part of the issue.
The PCB already provided the common ground. The USB issue may be related to NGFF key-B definition/handshakes. May need to look into it further.
Do you know if the M.2 connections for the USB communications are pulled low or high on the udoo board, or if they are left floating?
For B-key, if USB is not used, these two pins (7 and 9) are left open (nothing connected) and the M.2 card should ignore.
Just wanted to provide an update. I purchased a B+M Key to B key adapter so I did not damage the Udoo board/M.2 card when I originally soldered on my USB cable to pins 7 and 9. I believe this introduced an impedance mismatch which is why my USB would not enumerate. My final solution was removing the adapter, pulling wires 7 and 9 off the M.2 connecter and soldering directly to them. After doing so, my USB device successfully enumerated and I was able to get the USB interface off my M.2 card as well as the PCIE interface which I originally had. Thank you for the help!
