EMM Computers designed an XT clone that boots from USB using a CH376S module. The code for the option ROM is here.

alexanrs wrote on 2015-05-12, 14:05:

USB 1.0 isn't THAT useless. I've used flash drives on Socket 7 + USB1.0 systems before, and it is still faster and more convenient than floppies (specially because my main PC doesn't have a floppy drive... or controller). Network is still king though.

Seriously,

When I first got back into retro I was thinking I was going to put in usb 3.0 cards, usb 2.0 cards etc. but I discovered that the usb 2.0 cards actually just sit there slowing the system down even if not being used. Like a lot!! 3d mark scores increase 30% if you take it out.

It’s nuts.

I found a 3.0 card but pci slots are so scarce on these systems so finally I just settled on getting a internal hub for the usb 1.1 ports. And it’s perfect! It gives me like 8 ports. Highly recommend.

Re: Which USB 2.0 cards for old motherboards

Check this out

Plasma wrote on 2021-12-05, 20:44:

EMM Computers designed an XT clone that boots from USB using a CH376S module. The code for the option ROM is here.

Oooh! Thank you for the pointer.

I follow EMM on YouTube. HIs 8088 based projects are super interesting and very inspirational! Just FYI, he also sells his PCBs on Ebay (well at least Ebay US).

Also followup to my previous posting. There is a multi page thread about this board on the VCF. There is a hack of an additional 74LS11 NAND gate which fixes the incomplete decode of the ROM chip select. Bloody annoying to buy a "professional" card and find out that it has a serious flaw. Since most people won't use the ROM socket, they won't be aware or impacted.

There might be several versions of this board.

Mine has the CH375B, socket for 32x8 EPROM, 74LS125, 74LS139 and 74LS138. The ROM chip select address is not fully decoded (A19 and A18 are not connected).

The board whose schematics are pointed to on VCF uses a PAL/GAL16V8 for the decode rather than the separate TLL chips. A modified schematic shows the additional 74LS11 gate. So this does not apply to the above board, however I am sure a very similar fix will work.

Funnily enough, I had the thing working for the first time just a few minutes ago, using the CH375DOS.SYS driver. I had an empty FAT16 512Mb USB stick which I tried. CHKDSK failed, so I added the /F option to fix. I then plugged this USB stick into my main Win10 PC and copied a small number of DOOM files onto the stick. When put back in the old 486DX motherboard and booting using NWDOS7 on floppy, the driver executed and mounted the USB stick as drive C: . I was able to run DOOM. This is really great as I have no IDE ISA card for this motherboard. I have some possibly faulty Ebay purchases for this "new" 486 motherboard and I need to be able to get some diagnostic software onto this machine. Looks like the ISA to USB is "just the job" 😀 . Now I have to figure out which driver files I need for the ISA sound card.

I bought the USB ISA card from Ali Express. I got it to work.
DEVICE=CH375DOS.SYS @260 #07
@260 is the IO port you set with the jumpers. 260 is default
#07 is the interrupt you choose. No jumpers Just this parameter.
Only 3KB of RAM.

I tested the device with USB Flash drives and USB to CF Adapter.

I made a short video: https://youtu.be/SfqYkomlkDo

Jinxter wrote on 2022-03-24, 18:33:

I bought the USB ISA card from Ali Express. I got it to work. DEVICE=CH375DOS.SYS @260 #07 @260 is the IO port you set with the […]
Show full quote

I bought the USB ISA card from Ali Express. I got it to work.
DEVICE=CH375DOS.SYS @260 #07
@260 is the IO port you set with the jumpers. 260 is default
#07 is the interrupt you choose. No jumpers Just this parameter.
Only 3KB of RAM.

I tested the device with USB Flash drives and USB to CF Adapter.

I made a short video: https://youtu.be/SfqYkomlkDo

Just watched the video, and I'm bugged by the fact you didn't look into where the usb card you have puts the bios, ie which address.
In the text of the website it mentions 8KB of ROM for the bios and I'm left wondering if the due to the expected (eep)rom on the card versus the used one the data might not make it to the computer due to signal lines left high/low or even unconnected, causing a wrong address to be interpreted and thus the wrong data from the eeprom being sent to the computer.
Anyway, 👍 on the video and have fun with the usb card.
Though seriously 30KB/s is pretty f'n slow.

I found the EMM 86 Project first, then the different youtube Videos.

I prepare a new Video for the end of the week, because I was able to optimize the driver, it is now.... Much better 😀

LGR Blerbs takes a look at it--
https://www.youtube.com/watch?v=3W5ydPuqpTg

Verdict: Nifty but slower than a floppy disk

Looks like you could solder a set of header pins on there if you wanted to put a front port on your PC.

douglar wrote on 2022-05-23, 17:47:

LGR Blerbs takes a look at it-- https://www.youtube.com/watch?v=3W5ydPuqpTg […]
Show full quote

LGR Blerbs takes a look at it--
https://www.youtube.com/watch?v=3W5ydPuqpTg

Verdict: Nifty but slower than a floppy disk

Looks like you could solder a set of header pins on there if you wanted to put a front port on your PC.

Hi,

It seems that you did not read my post above 😀

Plasma wrote on 2021-12-05, 20:44:

EMM Computers designed an XT clone that boots from USB using a CH376S module. The code for the option ROM is here.

There's a new feature at hackaday.com:
https://hackaday.com/2022/05/21/building-your … xt-motherboard/

Jo22 wrote on 2022-05-23, 19:48:

Plasma wrote on 2021-12-05, 20:44:

EMM Computers designed an XT clone that boots from USB using a CH376S module. The code for the option ROM is here.

There's a new feature at hackaday.com:
https://hackaday.com/2022/05/21/building-your … xt-motherboard/

That is so cool.

Maybe some day we will have socket 7 diy boards :p

Hi,

So here is what I did with the Driver 😀

https://youtu.be/WNg8ROz0weg

Nothing like finding a new driver that gives you a 10x performance boost for free. Thanks for doing the research.

Did the new driver improve compatibility with newer USB drives?

Any news on using the option rom? Maybe it requires a specific eeprom.

Did you find a rear bracket that fits the card or did you just mount it "naked" ?

douglar wrote on 2022-05-25, 18:39:

Nothing like finding a new driver that gives you a 10x performance boost for free. Thanks for doing the research. […]
Show full quote

Nothing like finding a new driver that gives you a 10x performance boost for free. Thanks for doing the research.

Did the new driver improve compatibility with newer USB drives?

Any news on using the option rom? Maybe it requires a specific eeprom.

Did you find a rear bracket that fits the card or did you just mount it "naked" ?

There is a bracket project going on in the pi pico mouse adapter thread.

USB to Serial Mouse using the Pi Pico!

FreddyV wrote on 2022-05-25, 17:05:

Hi,

So here is what I did with the Driver 😀

https://youtu.be/WNg8ROz0weg

Thanks!

My card just came in yesterday from Aliexpress. I had the 3d printed bracket already printed beforehand. Sorry for the blurry pic.

douglar wrote on 2022-05-25, 18:39:

Nothing like finding a new driver that gives you a 10x performance boost for free. Thanks for doing the research. […]
Show full quote

Nothing like finding a new driver that gives you a 10x performance boost for free. Thanks for doing the research.

Did the new driver improve compatibility with newer USB drives?

Any news on using the option rom? Maybe it requires a specific eeprom.

Did you find a rear bracket that fits the card or did you just mount it "naked" ?

Hi.

Compatibility with New drive is Ok Just be carefull with the partition type and the OS Version.
I will add the partition type detection in the driver.

Somebody already did a bracket, i dont remember Who.

The ROM on this board can t be used as there is a bug in @ decoding.

Thanks for this Freddy! I’ll give your driver a try later today

FreddyV wrote on 2022-05-26, 06:06:

The ROM on this board can t be used as there is a bug in @ decoding.

Is the rom not being able to be used, a hardware problem or software?

FreddyV wrote on 2022-05-25, 17:05:

So here is what I did with the Driver 😀 https://youtu.be/WNg8ROz0weg

Wow, really nice work. Thank you.

Will you be working on making a boot rom?

Here is a USBISA card bracket. I am using it. Works fine.
https://www.thingiverse.com/thing:5350142