(03-16-2021, 06:02 PM)barray Wrote: @lupyuen has done some epic work in this space: https://lupyuen.github.io/articles/book
I can't tell if he got QSPI working, but there is certainly more than enough to get going there.
I've already seen that, great work!
(03-16-2021, 06:02 PM)barray Wrote: Me neither, we might be looking at USB-SPI interface chip initially: https://ww1.microchip.com/downloads/en/D...22288A.pdf
We should in theory be using something with USB support already, but the BL602 is nice simply because the community already works on it and it has everything else we need, as well as being RISC-V. Developing hardware for the BL602 should be as simple as just developing a 'hat' PCB - which makes it quite attractive as a starting platform: https://files.pine64.org/doc/Pinenut/NUT...%201.0.pdf
Attaching a USB 2.0 device interface over SPI may suffice, but we'd need something better than the MCP2210 you've linked above. It runs at Full-Speed USB 2.0 (12 Mbit/s), which is very slow; we'd really need a High-Speed USB 2.0 (480 Mbit/s) interface.
It wouldn't be the greatest thing in the world, for sure, but I agree with you on leaning toward the BL602. Basically, the new open storage device would be built on top of the already existing community work, increasing its value further. Also, that approach should make it possible to develop and release the new device (i.e. a "hat") faster, which is always good.
Using the BL602 should also allow the new USB storage device to be somewhat easily turned into some sort of a barebone NAS accessed over WiFi or even Ethernet. That would be another neat feature, if you agree.
Edit: One possible issue preventing the idea of making it as a "hat" could be the already present SPI flash on the BL602 "baseboard". There has to be some SPI flash already on the "baseboard", which would in turn prevent quad-SPI flash from being used on the "hat".