M2 Bifurcation Board

[jbutler]

Hi, I’m very interested in using the bifurcation support on the 5b to run a M.2 drive and an M.2 style 10gb nic. Has anyone been able to locate a M.2 x4 to dual M.2 x2 board / adapter?

Is this something radxa plans to release similar to their sata board for the e key slot?

[Semi]

I have not been able to locate one so I made one myself:

Radxa M.2 E key to SATA breakout card

Yes i did make some progress. I made a new PCB which now fits completely under the Rock5. I am able to boot from an NVME-ssd connected to two lanes while a JMB585 sata controller is connected to the other two lanes. I’m planning to use it as a NAS but i have only made some experiments, so i can’t say anything about reliability, especially since the power stage was designed for only one device. [IMG20230404164612] You can have a look at the files here: Files (altium.com)

[Dante4]

Believe me, it will be simpler to just use board that doesn’t require bifurcation to work

[jbutler]

@semi Were you able to get these made somewhere that also soldered on the connectors or did you have to do that yourself?

[dominik]

We are still looking for more insights about this board, have You had chance to test some m/2 devices? how they work and is that stable enough?
What about power?
Someone asked about differential pair, is that a problem like with USB?

@jbutler You can just drop @semi file to any good PCB maker and they will produce and assembly everything for You. Jlcpcb is charing about $55 for 5x ready to use boards. Of course You can solder that Yourself and get bare boards for about $8 + shipping. The only thing that You need to pay attention is board thickness - it have to be 0.8mm.

[Semi]

I did order them at JLCPCB and soldered them myself. But like @Dominik already said, you can have them assembled there.
I did not test it with different M.2 devices but I had my setup running with a sata SSD and a sketchy ATX-PSU for about a month. I have openmediavault running and I have had no problems so far.
The two lanes of each differential pair should have the same lenght. Since I make a 180° turn on the board and didn’t bother with length matching I ended up with a length difference of up to 1.5mm. The difference should be less than 1ps, meaning that the length difference should be smaller than 0.1mm.

[wong_disable]

Hi, I’m very interested in using the bifurcation support on the 5b to run a M.2 drive and an M.2 style 10gb nic. Has anyone been able to locate a M.2 x4 to dual M.2 x2 board / adapter?

I think I had done exactly what you asked for .
The bifurcation is painful, but works with some limitations.

The power supply is insufficient if you want to use both of the slots for nvme as RAID.
My NIC was limited to PCIe Gen2 for some mystery reason, but good enough for a decent OMV usage.