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Thread: Possibility of making clone MCA sound cards.

  1. #101

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    Might as well make a MCA to ISA slot box so you can use any ISA devices you want

  2. #102
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    Quote Originally Posted by rmay635703 View Post
    Might as well make a MCA to ISA slot box so you can use any ISA devices you want
    There are two things that make that difficult.

    The first is card configuration. The way IBM chose to do Plug-n-Play in the MCA standard makes that problematic. The first thing you need to make any ISA PIO based design MCA ready is to return a 2 byte ID at an address offset when the config strobe is asserted. That indexes an entry in a database of Adapter Description Files (ADF) to identify the card and it's resources. The ADF file can describe static reservations of I/O port addresses, DMA channels (called arbitration priories in MCA), IRQ assignments, and memory address. Or it can present dynamic config options that may be selected by writing to additional optional registers in the config space. For example a game port card might statically reserve I/O port 201h and not offer any dynamic card configuration. A drive controller, however, might present a series of 8 supported I/O address ranges selected by 3-bits in the config space so you can install more than one. The MCA 'setup' program (OEM specific) considers all possibilities based on adapters in the system, eliminates conflicts, and writes to the NVRAM a series of I/O config writes for each card on boot to set any dynamic options.

    The second big difference is each card must feedback an open collector signal when it is asserted. I allows any host to immediately abort the bus cycle for any accesses that are not going to be honored. Since ISA relies on long bus cycles, time-outs, and a series of resistor pulls to a deterministic state when undriven, it's hard to map this to a generic ISA implementation.

    Technically to implement a minimal PIO MCA card, you just need to return the card ID, route your card CSn back to OC driver on a pin, manually modify an ADF file to reserve any resources based on the current card jumper settings, and run setup with that file.
    "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

  3. #103

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    So I know it's been a while, but I've recently acquired a ChipChat 32 Sound Card. While that does solve my sound card issue it doesn't really help anyone else. So I figured at the very least I can provide some decent quality pictures of the front and back of the card as well as give any other information I can about this card.
    Does it have a standard game port, and if so, does it work well on most games?

    I have two P70s that would make unique game machines, but a lack of sound and joystick port brings that to a dead end. Both have the Kingston AOS 486 kits (one is 75 mhz and the other 133 mhz) and both have 64 mb of memory. Since they can boot to original 386-20 or 486, most games from early 80s to late 90s should run fine.

  4. Default

    Quote Originally Posted by Torch View Post
    Does it have a standard game port, and if so, does it work well on most games?

    I have two P70s that would make unique game machines, but a lack of sound and joystick port brings that to a dead end. Both have the Kingston AOS 486 kits (one is 75 mhz and the other 133 mhz) and both have 64 mb of memory. Since they can boot to original 386-20 or 486, most games from early 80s to late 90s should run fine.
    I don't have a joystick to test it with, but as far as I can tell it's a standard joystick port. It also works fine as a MIDI port as my SC-88 seems to work fine with it.

  5. #105

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    Quote Originally Posted by eeguru View Post
    There are two things that make that difficult.

    The first is card configuration. The way IBM chose to do Plug-n-Play in the MCA standard makes that problematic. The first thing you need to make any ISA PIO based design MCA ready is to return a 2 byte ID at an address offset when the config strobe is asserted. That indexes an entry in a database of Adapter Description Files (ADF) to identify the card and it's resources. The ADF file can describe static reservations of I/O port addresses, DMA channels (called arbitration priories in MCA), IRQ assignments, and memory address. Or it can present dynamic config options that may be selected by writing to additional optional registers in the config space. For example a game port card might statically reserve I/O port 201h and not offer any dynamic card configuration. A drive controller, however, might present a series of 8 supported I/O address ranges selected by 3-bits in the config space so you can install more than one. The MCA 'setup' program (OEM specific) considers all possibilities based on adapters in the system, eliminates conflicts, and writes to the NVRAM a series of I/O config writes for each card on boot to set any dynamic options.

    The second big difference is each card must feedback an open collector signal when it is asserted. I allows any host to immediately abort the bus cycle for any accesses that are not going to be honored. Since ISA relies on long bus cycles, time-outs, and a series of resistor pulls to a deterministic state when undriven, it's hard to map this to a generic ISA implementation.

    Technically to implement a minimal PIO MCA card, you just need to return the card ID, route your card CSn back to OC driver on a pin, manually modify an ADF file to reserve any resources based on the current card jumper settings, and run setup with that file.
    Nicely summarised. I looked at this in some detail quite a while ago and concluded it was way too complicated to do as well, without perhaps some micro controller logic that I know nothing about.

  6. #106
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    https://www.ebay.com/itm/ChipChat-16...orig_cvip=true

    Insanity.

    I am working on a MCA sound card. However I'm not going to post details until it's ready. ISA version comes first and I'm giving the project introductory talk at VCF-MW on Saturday.
    "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

  7. #107
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    I do not understand that auction. I really don't. I own more than one IBM Music Feature Card and Adlib Gold cards, and even a few cards more rare than those, and that auction end price just hurts my brain. $500 I can see due to rarity and demand, but $1800? Who in our hobby has that kind of money to spend on something that 1. isn't "name brand" authentic and 2. easily emulated?

    It's not like the MCA boxes were even that good for gaming! For $1800 I could build FIVE systems that run the gamut from 8088 to Pentium II and all have authentic functional soundcards.
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  8. #108
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    I can see a couple people who love IBM PS/2 machines pay that kind of money for a sound card they can game with. People spend more then a million for a car.

    Same thing with Amiga users paying hundreds for PPC cards just to play quake.
    What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
    Nubus/ISA/VLB/MCA/EISA cards of all types
    Boxed apps and games for the above systems
    Analog video capture cards/software and complete systems

  9. #109
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    Quote Originally Posted by Unknown_K View Post
    I can see a couple people who love IBM PS/2 machines pay that kind of money for a sound card they can game with
    I'm drawing blanks. I would expect anyone by that point with pockets that deep they would be funding a replica project.
    = Excellent space heater

  10. #110
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    Quote Originally Posted by NeXT View Post
    I'm drawing blanks. I would expect anyone by that point with pockets that deep they would be funding a replica project.
    Some people hate that replica/reproduction projects exist, though.

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