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> Why the eMMC? There is an M.2 E key but that's for wireless connection only. Is it a platform limitation that M.2 SSDs can't be used? Presumably very limited
by MobiusHorizons 2y ago
> Why the eMMC? There is an M.2 E key but that's for wireless connection only. Is it a platform limitation that M.2 SSDs can't be used?
Presumably very limited pcie bandwidth. You should think of this more like a raspberry pi than a pc motherboard.
E key slots typically provide 1 lane of pcie 2.0 (even on systems with 3.0 available), while m.2 is 4 lanes and frequently faster pcie 3.0
- haunter 2y ago> You should think of this more like a raspberry pi than a pc motherboard Thanks that makes perfectly sense! I kind of want to buy one now (too bad single 32GB boards can't be bought, minimum order is 256)
- MobiusHorizons 2y agoJust checked: looks like it does provide a full size pcie slot. My guess is that the intended use case is for developers testing compatibility. You could almost certainly plug in an nvme drive through an adapter to that full size slot (although booting from it would likely require a custom uboot build) but if you use up the one slot for storage, you can’t plug in any other peripherals to test.
- phire 2y agoIt's a 16x slot, but it only provides 4 lanes of PCIe 3.0 Appears to be a SoC limitation, which only has a single 4x PCIe 3.0 interface, and doesn't appear to support bifurcation (splitting into two 2x slots, or four 4x slots). You could probably throw a PCIe switch on it, but PCIe switches are expensive. The SoC wasn't designed for this product, it was designed by 3rd party company for computer vision/robotics/manufacturing use cases.
- brucehoult 2y agoYeah, the Intel Horse Creek chip with the same SiFive P550 cores was probably much better on I/O -- and likely DDR IP as well, if they used their good stuff -- but for some reason Intel decided not to go to mass production on them, despite showing off a working board at a trade show in IIRC September 2023.
- fer 2y ago> You should think of this more like a raspberry pi than a pc motherboard. For the price tag I think it should be more like a motherboard. Especially when Raspberry Pi 5 has official m.2 hats.
- MobiusHorizons 2y agoThis is effectively an industrial dev board not a product for normal users. They are usually expensive because of low volume
- zamadatix 2y agoYou can connect M.2 NVMe, it just doesn't have a dedicated slot. If you're looking for a cheap device to plug a bunch of different PCIe devices into a RISC-V development board is probably not your ideal pick, look at a normal computer.
- connicpu 2y agoSometimes not even that. On my motherboard the E key slot is just USB. EDIT: Originally said USB3, but it's actually USB 2.0.
- MobiusHorizons 2y agoI believe the slot usually passes 4 wire usb2 as well as 1 lane if pcie. I had no idea usb3 was an option. How does that affect compatibility?
- connicpu 2y agoAh my mistake, it is in fact USB 2.0. There does exist an M.2 key which can provide USB 3, but that's Key B not E.