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USB to IDC 20 / Centronics?

Posted: Thu Oct 10, 2019 2:57 pm
by Dbug
Question: I've seen a bunch of USB to centronics cables, designed to use old printers on modern PCs.

Do you think it would be possible to hack one of these things to make it work with the MCP 40, like drawing and printing directly from a PC on the Oric printer, or would that fail miserably?

Re: USB to IDC 20 / Centronics?

Posted: Thu Oct 10, 2019 7:59 pm
by Chema
I don't see why it shouldn't. After all these printers respond to commands sent through the paralell port, so it is a matter of writing the appropriate software (or driver!). And knowing the commands, of course :)

I don't see the benefit of that, however. What do you have in mind, Dbug? I bet something evil, as usual :twisted:

Re: USB to IDC 20 / Centronics?

Posted: Thu Oct 10, 2019 8:01 pm
by iss
The short answer is yes, ... almost :). The problems are:

1. I think there is no "ready-to-use" USB to IDC-20 cable. The best choice is to use USB to DB25 female
with an additional converter DB25 male to IDC-20 <- NOTE: DON'T BUY THIS ONE! It's NOT for printers, the link is for visual reference only.
I can make one for you and send it together with the OricExos (latest next month when audio mixer is ready ;)).
I have already one USB to DB25 and used it to connect one very old JTAG programmer for CPLD's - overall it worked.

2. I doubt there are MCP-40 drivers for Windows :), you need to use raw printer driver (I think in Win 7/8/10 it's called "Generic text only" printer driver). As result no fun MS Word printing, but you will be able to send directly to printer files with MCP-40 specific commands just like from Oric :).

Another not too difficult option can be to use mini/micro/nano Arduino as USB emulated serial port to IDC-20 parallel port. In this case it will be possible again to send raw commands to MCP-40 like this: copy /b file.bin COM15

Re: USB to IDC 20 / Centronics?

Posted: Thu Oct 10, 2019 8:20 pm
by Dbug
I doubt there are MCP-40 drivers for Windows :), you need to use raw printer driver (I think in Win 7/8/10 it's called "Generic text only" printer driver). As result no fun MS Word printing, but you will be able to send directly to printer files with MCP-40 specific commands just like from Oric.
Obviously the idea was to send direct raw commands, after all it's what the MCP-40 supports, even for drawing lines it's all in the pseudo parametric language :)

LPRINT CHR$(18);"M240,0"
I don't see the benefit of that, however. What do you have in mind, Dbug? I bet something evil, as usual :twisted:
Obviously, why do you even ask :D ?
That's kind of related to the question on where to get the paper. I checked all the links, but pretty much all the time I end up with more than 35 euros to pay, knowing that in Norway if something is declared more than 350 NOK, you have to pay 25% VAT on the entire cost of the product + shipping, plus some administrative fee of about 160 nok (say 16 euros), which makes these things quite expensive quite fast.
I can make one for you and send it together with the OricExos (latest next month when audio mixer is ready ;)).
That would be cool, it's not super urgent, just another of my two many side projects!

Re: USB to IDC 20 / Centronics?

Posted: Fri Oct 11, 2019 8:04 am
by iss
About the USB to MCP-40 converter: I just realized that maybe there is even better solution.
If the back connector of your MCP-40 is like this ORIC-1 model:
mcp-40.jpg
Then you can use this appropriate converter:
USB2PRN.png
USB2PRN.png (92.12 KiB) Viewed 9173 times

Re: USB to IDC 20 / Centronics?

Posted: Fri Oct 11, 2019 10:01 pm
by Dbug
I don't think it's a standard connector, it was probably added later.
My Atmos variant definitely has the same connector as what is on the back on the Atmos.

Re: USB to IDC 20 / Centronics?

Posted: Fri Oct 11, 2019 10:55 pm
by iss
Maybe it's inside like this one HERE.
Can you take a picture from backside of Oric and MCP-40 how they are connected with the ribbon cable.
Important is to see where goes the first line (i.e. the red wire).

Re: USB to IDC 20 / Centronics?

Posted: Sat Oct 12, 2019 7:08 am
by Dbug
You can see the cable and connector in the video here at 10:57: