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Thread: Intrest in new ISA cards?

  1. #11

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    Quote Originally Posted by Stone View Post
    There are DOS drivers for the ordinary PCI USB ports.
    Rather useless in 8088 or 286 PCs...

  2. #12

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    As far as tandy graphics go, since I plan to use an FPGA, I should technically be able to emulate any video card you want. However, I'm not sure how Tandy graphics work, or if they are even compatible with the ISA bus. I'm not really educated in that area.

    For the USB card, I was thinking that it might present itself to DOS as something like a zip drive. It is always assigned a drive letter, but if you try to access it when you don't have a flash drive in it, it just returns a "drive not ready" message.

  3. #13
    Join Date
    Apr 2018
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    Los Angeles, CA
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    Quote Originally Posted by Xacalite View Post
    Rather useless in 8088 or 286 PCs...
    Yeah, any computer I have that has PCI also supports windows.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

  4. #14

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    If anyone were going to make an FPGA-based ISA video card, my suggestions for extra modes / support would be:
    • Hercules InColor - since you'd be outputting to a colour display you might as well emulate the InColor rather than a mono Herc. As far as I know it's fully back-compatible.
    • Wyse 700 - 1280x800 resolution and a choice of two 16x16 fonts in text mode.

  5. #15
    Join Date
    Mar 2011
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    Atlanta, GA, USA
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    I've had the idea of a modern ISA video card before and gave some serious thought and research to it. I don't have time to be a primary on such a project, but I am up to contribute if you get serious about it. Some things to consider:

    - Please use proper level translation on the ISA bus. There are a lot of ways to bridge 3.3V and 5V including quick-switches and PCI clamp diodes built into some devices. However the best method by far for signal integrity is dual voltage rail '245 type directional buffers. I've tried just about every method and the ghosts in the machine will drive you crazy.
    - I don't have personal experience with direct Spartan 6 driving TMDS outputs on regular GPIOs. However I caution against it a little as TMDS is 10:1 minimum over dot-clock. 720p60 and 1080p30 are 74.5 MHz. 745 MHz makes everything harder. A dedicated HDMI MAC where you can run the dot-clock * 28 lines is easier. No one rain drop causes the flood. Every little bit of ease helps.
    - Memory bandwidth is the largest concern. Any thing worth doing is worth doing right. Don't arbitrarily gimp the project by limiting the output resolution because of other factors. 74.5 MHz * 24 bits per pixel = 223.5 MBytes/s memory bandwidth. It's difficult to get that with SDR SDRAM unless you go 16 or 32 bit wide. DDR(1) is possible and still available in leaded parts. DDR2+ is BGA only. Any memory subsystem will have to run >100 MHz * 16 bit for SDR and 8 bit for DDR. It presents challenges. Don't underestimate.
    - Follow the evolutionary lead of the standards themselves. Start with CGA or MDA only. Then incrementally add HGA, EGA, base VGA, MCGA, SVGA, etc. Don't try and emulate a Tseng ET4K on day #1.
    - There are lots of VGA cores on opencores.org. But most aim at just output clock generation with frame buffer support and not original IBM register compatibility. Two that do I recommend referencing that do, are:
    http://wacco.mveas.com/
    https://github.com/asicguy/gplgpu
    - HDMI can transport sound in HBI/VBI packet areas. Most HDMI MACs have both I2S and S/P-DIF inputs. Adding connections between FPGA and those inputs is trivial. But also consider some basic DMA/IRQ connectivity on the ISA bus for sound card emulation as well.
    - Don't try and put every feature on your list into one card. Feature creep will kill it. In fact, maybe not add to revision 1 after all.
    - Start with a soft-cpu core in the FPGA to exercise things /unit test things both from the soft core -> output and the ISA -> soft core directions.
    - Design from the start considering write caching. That's how most fast SVGA cards like the ET4K got their performance. Writes would always assert ZWS and READY immediately while the ISA write would buffer pending multi-plex availability to external RAM. Any read would block (negating READY) until the write cache emptied and the bus was again available before being serviced.

    -Alan
    "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

  6. #16
    Join Date
    Jul 2013
    Location
    Brisbane, Australia
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    Quote Originally Posted by johnkiniston View Post
    On your video card could you include PCJr/Tandy graphics?

    I lack either a PC Jr or a Tandy 1000 series machine and would love to play games that used the enhanced graphics and sound on my Kaypro PC or my IBM 5155.
    Speaking of the IBM 5155, having the internal connector for the inbuilt CRT would be a nice feature to have on any modern ISA video card. Probably not a huge market for it but for 5155 owners like myself it would definitely benefit from having more options when it came to replacing the original IBM CGA card.
    AtariPC.net
    Atari PC | IBM Compatible Series

  7. #17

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    HDMI is a licensed socket btw

  8. #18

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    Quote Originally Posted by pearce_jj View Post
    HDMI is a licensed socket btw
    Yep, found that out today. HDMI licensing fees are absolutely ridiculous. I am thinking about going with DisplayPort instead. No licensing fees, and it is backwards compatible.

  9. #19

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    Quote Originally Posted by pearce_jj View Post
    HDMI is a licensed socket btw
    yeah we had this discussion with him on vogons. DVI however is not licensed!

  10. #20
    Join Date
    Mar 2011
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    Atlanta, GA, USA
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    Quote Originally Posted by dkarguth View Post
    I am thinking about going with DisplayPort instead. No licensing fees, and it is backwards compatible.
    I think you mean DVI. DisplayPort is a constant clock fully packetized protocol. Very different but open.

    DVI and HDMI share the same protocol lineage.
    "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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