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Lo-Tech ISA-USB

eglioltereg said:
Good day everybody.

So I build this kind of adapter by the scheme of lo-tech (https://www.lo-tech.co.uk/wiki/Lo-tech_ISA_USB_Adapter)
And of course I want to test it, but find the problem that I can't download bios and flasher for this device from the lo-tech site.
Is there chance somebody could help me with this?
Click to expand...

This ISA to USB adapter is currently being sold on various Chinese websites such as taobao. You can also find the card on eBay occasionally. I bought a few from taobao and they are actually quite useful. There is an XT-compatible DOS driver that can assign a DOS drive letter to a FAT-formatted USB thumbdrive that is less than 512MB. There is also a slot for a 27C64 boot ROM. I was able to make my 286 boot from USB by using the provided BIOS, albeit with some serious limitations.

I write about my experiment on my blog here http://www.toughdev.com/content/201...8-bit-isa-bus-using-ch375-isb-to-usb-adapter/ - you can also download the driver, BIOS, and documentation on the same page.

This is a video showing how my 286 boots from USB using this card:

 
Emm. It is very interesting, amigo, but I didn't get how you flashed bootrom?
lo-tech design allows to flash it via DOS on installed pc with it own flasher, do you know where can I get some?
 
You can just use any EEPROM programmer, and program a suitable BIOS to a 27C64 EEPROM, then install it onto the socket. The BIOS provided by lo-tech is not compatible with my version of the card and I ended up using another BIOS downloaded from a Chinese website which works (after some modifications). See the link I provided earlier for details.
 
made 4st copy of that plate - it is boot from bios(rom works) but doesn't see flash
also doesn't works with ch375 sys (port 2c0 as written on lo-tech site)
any ideas? does lo-tech should work with ch375 driver? is any way to test the board?
 
I'd forget about the boot rom bios, It has issues, Use the CH375DOS.sys driver in the "No Interr" folder on an XT machine, It's V1.9A IIRC, In your "Config.sys" you should have at least:

DEVICE=C:\DOS\CH375DOS.SYS @2C0 %1
FILES=30
BUFFERS=15

That's assuming the dos driver is in the dos directory, The %1 on the end is the speed setting, You may have to play with that.
The dos driver works fine with the lo-tech card, Slow in an XT but better in a 286 >. Make sure you have all the right components in the right places and your solder joints are good. What error messages are you getting?.
 
Malc said:
I'd forget about the boot rom bios, It has issues, Use the CH375DOS.sys driver in the "No Interr" folder on an XT machine, It's V1.9A IIRC, In your "Config.sys" you should have at least:

DEVICE=C:\DOS\CH375DOS.SYS @2C0 %1
FILES=30
BUFFERS=15

That's assuming the dos driver is in the dos directory, The %1 on the end is the speed setting, You may have to play with that.
The dos driver works fine with the lo-tech card, Slow in an XT but better in a 286 >. Make sure you have all the right components in the right places and your solder joints are good. What error messages are you getting?.
Click to expand...

I managed to get the BIOS to work after a lot of trials and errors. Once I know its limitations, it seems to be stable enough for my uses. On the other hand. the CH375DOS.SYS driver is very easy to use and should work without hassle, if you use it on a USB thumbdrive with a single FAT-formatted partition that is 512MB or less. Using it on a larger partition will cause the driver to freeze the system.
 
mdanh2002 said:
I managed to get the BIOS to work after a lot of trials and errors. Once I know its limitations, it seems to be stable enough for my uses. On the other hand. the CH375DOS.SYS driver is very easy to use and should work without hassle, if you use it on a USB thumbdrive with a single FAT-formatted partition that is 512MB or less. Using it on a larger partition will cause the driver to freeze the system.
Click to expand...

Yes i got the Bios to work also after a lot of faffing about but it has issues, Using the DOS driver i had no problems in using 1Gb and 2Gb thumbdrives with a single partition, I also had 2.5" hard drives connected to a USB adapter and external PSU working fine, On my lo-tech board i replaced a couple of capacitors to give more power at the USB port so the external power was no longer needed with the 2.5" drives i tried, I even had it booting from a 2.5" drive but with issues. It's a shame the project never went any further.
 
Malc said:
Yes i got the Bios to work also after a lot of faffing about but it has issues, Using the DOS driver i had no problems in using 1Gb and 2Gb thumbdrives with a single partition, I also had 2.5" hard drives connected to a USB adapter and external PSU working fine, On my lo-tech board i replaced a couple of capacitors to give more power at the USB port so the external power was no longer needed with the 2.5" drives i tried, I even had it booting from a 2.5" drive but with issues. It's a shame the project never went any further.
Click to expand...

My card doesn't like thumb drives that are 512MB and above, both when using the BIOS and CH375DOS.SYS. I think the firmware on the card has some issues interpreting CHS values for larger drives.
 
mdanh2002 said:
My card doesn't like thumb drives that are 512MB and above, both when using the BIOS and CH375DOS.SYS. I think the firmware on the card has some issues interpreting CHS values for larger drives.
Click to expand...

Thinking about it i remember finding 2 seemingly slightly different builds of the CH375DOS.sys v1.9x driver, Both had the same version # and build date but 1 had a time stamp of a few hours later and 1k difference in size, Just wondering what size / version / date and time stamp does the dos driver you are using have ?, I didn't know the chinese board had a firmware chip onboard. How are you configuring your flash drives.
 
eglioltereg said:
I'm getting message some kind of: "Bad I/O port" by driver ch375
Click to expand...

Check the address of the CH375 passed to the driver (e.g. the @ part of the DEVICE command) and make sure it matches the card address. The low-tech version places the card’s IO port at addresses 2C0-2C8h with a 32KB BIOS at either C800h or D800h. On the Chinese version of the card, the address can be chosen between 260h/270h/280h/290h via jumpers.
 
eglioltereg said:
I'm getting message some kind of: "Bad I/O port" by driver ch375
Click to expand...

Make sure the boot rom is disabled and just use the CH375DOS.SYS driver, See my post #7 in this thread, Do not connect a flash drive and power the computer up, Post the exact error message you see.
 
Looks like your isa-usb card is not working, The driver can not find your card or at least the CH375B chip, Can you post pics of both sides of your isa-usb card, clear good pics showing all components on both sides.
 
It is strange but my card is working with it ROM - rom is flashed, and trying to boot.IMG_20180723_214517_HDR.jpgIMG_20180723_214509_HDR.jpgIMG_20180723_214533_HDR.jpg
Second side is empty
 
I was under the impression that you had a " LO-TECH " isa-usb card, That is not a lo-tech card, Where did you get that from ?.
 
There is no original lo-tech isa-usb, I suppose.
This is my own copy of that card, made by lo-tech design.

Any ideas how to find the problem?
 
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