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Thread: Possibility of making clone MCA sound cards.

  1. #11

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    You can use a parallel port sound card -- such as this one which emulates AdLib and Sound Blaster:



    Or this new one which emulates only AdLib but is readily available:

    http://www.serdashop.com/OPL2LPT

  2. Default

    Quote Originally Posted by PeterLI View Post
    There are many obstacles. ISA cards are easily designed / supported / produced because there were and are so many. Replicas are therefore straightforward for 8BIT cards (not a lot of components and readily available at that: relatively few traces: surface only). IBM PC bus (8BIT ISA) is extremely well documented. A MCA card would probably be hard to design, and ADF would need to be programmed / cloned and proprietary CT / Roland chips (CT5320 / CT5330 / MPU-IMC) would require serious retro identification / engineering / hacking.
    True, though looking at some of the cards it might not be so bad. For example the AdLib card as far as I can tell uses off the shelf components that can still be found somewhat easily:



    The issue here is that there's no pictures of the backside I can find. If you had that it might be rather easy to put together a clone. And in doing that you might even be able to somewhat figure out the pinout of the bus controller chip. Which that might open the door for other clones. I'd imagine for the ADFs you could probably hijack the existing ones if you made a proper 1:1 clone.

    Quote Originally Posted by PeterLI View Post
    We looked into a MCA and PCI MIF-IPC-A clone a few years ago but gave up on the idea: too complicated / time consuming / cost prohibitive. Check out www.vogons.org: AdLib, MPU-401 (HardMPU, Music Quest PC MIDI Card), GUS and other clones have been developed / produced there. Have yet to see an aftermarket MCA PCB though. With a MPU-IMC clone (with lots of components / traces) this is only half the equation: a MPU-IMC BOB is another requirement. A CT5320 has far fewer components / traces but good luck locating the ICs.



    https://en.m.wikipedia.org/wiki/Micr...l_architecture

    VCFED history: http://www.vcfed.org/forum/archive/i...p/t-40572.html.
    I was actually thinking of making this topic on VOGONS as well. For the hard to find ICs, there is always the route of using an electron microscope to figure out what the chips are doing. It might sound extreme but this was done with the SNES expansion chips to help improve emulators. Though it would probably be hard to get the enthusiasm behind MCA sound cards for that.

    At the very least, documenting all the MCA sound cards with good high quality pictures of the boards and ICs probably wouldn't be a bad idea in general and at that point they'd be there for anyone wanting to take on such a project.

    Quote Originally Posted by glitch View Post
    Part of what makes MCA sound cards so expensive is just that they're rare. Who knows if the people buying them are really using them.
    That is a good point. Though there are quite a few ways to gauge interest such as kickstarter and what not.

    Quote Originally Posted by glitch View Post
    If anyone were to pursue a hobbyist-driven MCA interface, I think, as I've discussed elsewhere, that probably a MCA -> ISA bridge would be the smart way to go, with a MCA board that carried one or more PC/104 modules. That way, the expensive part only has to be made once, and any number of off-the-shelf interfaces could be plugged in, including SoundBlaster-compatible sound.
    The only thing I'd see being awkward with that is how would you mount the ISA card?

    Quote Originally Posted by vwestlife View Post
    You can use a parallel port sound card -- such as this one which emulates AdLib and Sound Blaster:

    Or this new one which emulates only AdLib but is readily available:

    http://www.serdashop.com/OPL2LPT
    Yes, but they're not ideal. Especially if you have a 286 system which requires individual game patching.

  3. #13
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    Quote Originally Posted by TrekkiesUnite118 View Post
    The only thing I'd see being awkward with that is how would you mount the ISA card?
    PC/104 boards are electrically ISA, but are smaller, stacking modules, like this:


  4. #14

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    Probably one of the simplest cards I have is the IBM dual serial card. AFAIK its a a couple of UARTs and some TTL logic, BUT has a chip labeled "IBM 66X2891". Datasheet anyone?:
    Dual Serial.jpg
    I also have an RM Ethernet card that as far as I can tell is mostly TTL, but also a few PALs. Thanks to Chuck (g) these can be reverse engineered. But I have no idea if this card even works. I would guess being British and a niche product it would be difficult to find drivers and verify:
    RM Ethernet.jpg
    Sorry about the terrible images. I just don't seem to be able to press the shutter and keep a steady hand and keep it in focus while inside. If there's any interest i can take better images.

    I would agree that MCA-to-ISA is the way to go. But I doubt there's going to be that much interest.

    Edit:
    The PC/104 is a very elegant idea but availability of sound cards? I would suggest a standard ISA connector, perhaps on a ribbon, or a tall MCA card that you then mount the ISA card upside down. I dunno. There are now pcie-to-pci adapters that mount a couple of PCI cards in a 5.25" bay. There are various options.
    Last edited by mR_Slug; January 28th, 2018 at 05:56 PM.
    Looking for: OMTI SMS Scientific Micro Systems 8610 or 8627 ESDI ISA drive controller, May also be branded Core HC, Please PM me if you want to part with one.

  5. Default

    Quote Originally Posted by glitch View Post
    PC/104 boards are electrically ISA, but are smaller, stacking modules, like this:
    Ah ok, that makes a lot more sense. That wouldn't be too bad then.

    Looking at the Sound Blaster cards, they might not be too bad either. Most of the chips on them are identical to their ISA counterparts, the only thing special is the bus controller chip. The CT5330 seems to use a proprietary chip, but the CT5320 uses a similar chip to the Adlib card, the CHIPS 82C612. Which it looks like the datasheet to it is available here:

    http://ps-2.kev009.com/ohlandl/Unsor...611-82C612.pdf

    I stumbled across it in this thread:
    http://www.vcfed.org/forum/showthrea...ge-chips/page2

    Both those chips seem to be available on a few different sites including ebay. I'd imagine if worst came to worst someone could get a couple of cheap ISA sound blasters to harvest chips from and make a prototype CT5320 clone. With the pinout from the datasheet of the MCA bus chip you'd really just need to see both sides of the MCA Sound card board to get an idea of what's doing what.

  6. #16
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    Quote Originally Posted by glitch View Post
    Part of what makes MCA sound cards so expensive is just that they're rare. Who knows if the people buying them are really using them.
    Well seeing the massive push in the last few years for "retrocomputing" (just typing that makes me ill) and hipsters paying crazy money for IBM machines because in their minds IBM was the best of the PC platform [citation needed], they are now setting up their little boxes to play Commander Keen and Doom and realizing just how unfriendly MCA is.
    They're paying crazy money for the machines and I assure you they are paying just as much for a sound card.
    = Excellent space heater

  7. Default

    Quote Originally Posted by NeXT View Post
    Well seeing the massive push in the last few years for "retrocomputing" (just typing that makes me ill) and hipsters paying crazy money for IBM machines because in their minds IBM was the best of the PC platform [citation needed], they are now setting up their little boxes to play Commander Keen and Doom and realizing just how unfriendly MCA is.
    They're paying crazy money for the machines and I assure you they are paying just as much for a sound card.
    Then there's people like me where it's simply the PC I grew up with. My dad got the PS/2 Model 50 back in the late 80's when he sold insurance for New York Life. If I remember correctly there was a serial modem with it years ago for hooking into their system remotely. While it may not have been a popular home system, it was very popular in offices. I remember just about any office my parents worked in growing up had a bunch of PS/2 systems, usually Model 50s or 70s. Even in some cases some upgraded 486 50s that ran Windows.

    They wanted to trash it years ago and I decided to take it instead.

  8. #18

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    Good luck! Let us know how it works out! Contact Bryce on AmiBay. He is an engineer and might be up for the challenge. In case of the MIF-IPC-A replica we had a technical reference which really helped. Perhaps https://www.lo-tech.co.uk is up to the challenge as well.

    A kickstarter would not generate a lot of interest probably (MCA sound is deep niche). Check out the IBM PS/2 newsgroup also. Once I provided feed capital for Project MPU and confirmed success a cheaper Asian (ironically also NL based) version and later also the MIF-IPC-B followed.

    ftp://ftp.oldskool.org/pub/drivers/R...e%20manual.pdf

    Another thing (practically) is that ISA prototype boards are readily available. No idea where a MCA board could be sourced.
    Last edited by PeterNC; January 28th, 2018 at 06:36 PM.

  9. Default

    Quote Originally Posted by PeterLI View Post
    Good luck! Let us know how it works out! Contact Bryce on AmiBay. He is an engineer and might be up for the challenge. In case of the MIF-IPC-A replica we had a technical reference which really helped. Perhaps https://www.lo-tech.co.uk is up to the challenge as well.

    A kickstarter would not generate a lot of interest probably (MCA sound is deep niche). Check out the IBM PS/2 newsgroup also. Once I provided feed capital for Project MPU and confirmed success a cheaper Asian (ironically also NL based) version and later also the MIF-IPC-B followed.

    ftp://ftp.oldskool.org/pub/drivers/R...e%20manual.pdf

    Another thing (practically) is that ISA prototype boards are readily available. No idea where a MCA board could be sourced.
    I'll try making a similar topic on Amibay and see where it goes. As for prototype boards, you'd probably have to make your own. Though just going off of plain looks, MCA isn't that far off from PCI. So maybe you could rig a PCI prototype board to work?

  10. #20
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    Quote Originally Posted by TrekkiesUnite118 View Post
    Though just going off of plain looks, MCA isn't that far off from PCI.
    Then looks are very deceiving. MCA is light-years from PCI. It's really a close cousin to ISA. Forgetting the DMA interface (which would not apply to Adlib anyway), MCA is ISA with a few 8-bit registers. One returns a static board ID and the others are optional to soft-configure IRQs and DMA channels. A small 5V PLD like a ATF150x could easily do the job for a simple PIO board. Other cards used SPLDs or even discrete logic. The Roland intelligent MIDI board (MPU-IMC) is a good example of discrete logic, fixed I/O addresses and interrupts, and all the ADF file does is make a fixed reservation in the setup disk utility.

    MCA is pretty well documented in the PS/2 technical references.
    "Good engineers keep thick authoritative books on their shelf. Not for their own reference, but to throw at people who ask stupid questions; hoping a small fragment of knowledge will osmotically transfer with each cranial impact." - Me

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