[Thomasz] took a analysis on the Raspberry Pi four and realized the brand new USB 3.zero chip is hooked up to the PCI Converse interface on the SoC. That is, in the event you deal with this chip and also you may properly presumably properly non-public acquired some very beautiful wires, you may properly presumably properly presumably patch in an actual PCI Converse slot. Hanging off the chip is simple ample with a scorching air gun, even though a couple of caps did acquire tousled. Throw that in an ultrasonic cleaner, and also you may properly presumably properly non-public acquired a easy canvas to work PCI magic.
This hack requires six wires, or three differential pairs, there’s a reference clock, a lane zero transmit, and a lane zero rating. Working backwards from a PCI Converse riser, [Thomasz] traced out these connections and soldered a couple of wires in. On the Pi side, a couple of capacitors have been required to be compliant with the PCI Converse spec, nonetheless the soldering isn’t too execrable. It’s probably you may presumably properly attain a lot with a small tip on an iron and a microscope.
The Pi was efficiently wired as a lot as a PCI Converse riser card, together with the traces for floor, 5V, hyperlink reactivation, and an impression staunch signal. Basically essentially the most attention-grabbing ingredient left to achieve was to proceed in a PCI card and take a look at. This didn’t bolt together with anticipated, given that PCI Converse adapter didn’t adore being enumerated by the Raspberry Pi kernel. In subsequent experiments, an Adaptec SAS controller labored. Does this recommend exterior graphics playing cards for the Pi? No, not quite; proper this is easiest one lane of PCIe, the place as a lot as date graphics playing cards require an x16 slot for the proper efficiency. Unexcited, in the event you’ve ever wished a SCSI card for a Pi, proper this is the proper possibility but.