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cnlohr / rv003usb

CH32V003 RISC-V Pure Software USB Controller
MIT License
436 stars 43 forks source link

USB Mass Storage support #41

Open jonnor opened 7 months ago

jonnor commented 7 months ago

The current code has support/examples for HID class devices. Would it be possible/feasible to implement Mass Storage Class on top of the existing core USB code? Or are there any particular challenges or limitation forseen with that?

My use case is a data logger. I would write to a small (1 MB) FAT32 filesystem to external SPI flash. And then to expose that over USB, to allow copying the logs over to a computer.

cnlohr commented 7 months ago

It is absolutely theoretically possible, but, last time I tried, neither Windows nor Linux (for different reasons) would let me make a mass storage device, since they really wanted bulk endpoints for the data transfer.

It's totally possible some other descriptor voodoo would work! I only spent about 15 minutes trying.

cnlohr commented 7 months ago

Apparently I can't build function rv003usb's here :'( I have some GCC version that doesn't work right. I guess I'll have to debug tonight.

BogdanTheGeek commented 6 months ago

Maybe this would help: https://github.com/brendena/pico_drag_n_drop_programmer/blob/main/msc_disk.c

cnlohr commented 6 months ago

Super curious if that can be made to work with USB-low-speed.