I bought one of these exact boards from China a few months ago. They are a little pricey at around $25-30. Also recently I bought a 486DX and motherboard on Ebay. I am hoping that this card, via the USB stick, will give me an easy way to transfer DOS programs downloaded on my main PC to the 486. I am still sorting out the 486 system, and just yesterday my VLB IDE and floppy card arrived. I'm still kicking myself when I rhink of all the VLB cards and floppy cards I must have thrown out back in the 90's 🙁 . Currently I do not have a hard disk connected, so I can only boot from floppy. Now I have the VLB IDE card I will try to get this working and install NWDOS7 (from my original disks).
Once I have NWDOS installed I will try the mentioned driver.
I had sort of assumed that the USB would need to be formatted in FAT12 (FAT16?) format and could be made bootable just like a floppy or hard disk.
Out of curiosity I traced out the connections to the ROM socket. I have a bit of a suspicion that the chip select for the ROM is not properly (fully) decoded, as the ISA connectors for A18 and A19 are totally un-wired! I would have thought that it was necessary for these top two address lines to be part of the chip select logic, otherwise you could get aliasing elsewhere in the memory map (where the RAM is) and possible contention.
FYI the CH375 is based on a 8051 core with USB circuitry added on. It contains firmware which contains a sort of BIOS for USB disk like access (read and write sectors). You can communicate with the chip (commands and data) either using the serial I/O feature or using the parallel I/O feature which has 8 data bits and one address line. So although there might be a lot of overhead it makes it really easy to use in a homebrew CPU board or with an Arduino.
I was hoping that this device might be supported by something like the XTIDE Universal BIOS and allow the USB stick to be booted from like a floppy or hard disk. This would require an option ROM, and as mentioned I think a ROM in the socket would work but might cause other contention problems. Thankfully I have a network card with a ROM socket, which I think I would trust more.
So if anyone can give any advice about using this card and how to transfer data via the USB stick, that would be most helpful. I am interested in recommendations of any tools (ideally free) which allow the USB to be formatted with an old version of DOS.
Once I find out more I will re-port.
BTW I forgot to mention, it's NOT a general purpose USB port, it has the 8051 processor core and firmware which only supports "disk" I/O.