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Recent content by mogwaay

  1. M

    Has anyone made any 16kB games on cassette for the IBM PC?

    Not sure if this is interesting to you, but I converted the PC Booter version of PC-MAN to cassette a while back. https://github.com/moogway82/pcman_tape Only tested on my own XTjr homemade PC which can run IBM Cassette BASIC and MAME emulation of a 5150. Not sure of minimum RAM, I think...
  2. M

    Project to create an ATX 80286 mainboard based on the IBM 5170

    Just a suggestion, if you ever fancy making a VGA controller chip, you could hop on to the Graphics Gremlin project which has CGA & MDA implemented failthfully in FPGA on an ISA card. I think the original author, TubeTime/schlae intended to add EGA and VGA however I think he found the BIOS...
  3. M

    Project to create an ATX 80286 mainboard based on the IBM 5170

    This is amazing! Having an open source 286 custom chip set that can be synthesized using commodity CPLDs is so brilliant! Such a cool project and I think many folks (incline when I find time and money) would love to have a go at building. Bravo! 🥳 Very impressed (and relieved for your bank...
  4. M

    Spectrum ZX 128k - complete newbie

    That's a really weird screen to get. I have a +2A too and have never seen that before. It might be video ram, but it looks like it's managing to do quite a lot and I would think you'd get more random artifacts on the screen... You could try running the built in self test by holding down Break...
  5. M

    Project to create an ATX 80286 mainboard based on the IBM 5170

    Amazing work! I'm impressed that you got this much working on a first go - just shows how much effort you've put in to check your work, outstanding 👏 Good luck on the debugging, I'm sure you'll find your gremlins!
  6. M

    Project to create an ATX 80286 mainboard based on the IBM 5170

    Can I just say this is a very cool project, all the best with it - your other 8088 boards look fantastic, as someone who made a 8088 computer (XTjr based on the Xi8088) much more professional than my jobbie! Im also looking into using Atmel ATF15xx CPLDs for one of my other projects, and as I'm...
  7. M

    Converting a PC Booter Game to Cassette Tape

    Wow, great find, that's awesome! Hope you can get it working, would love to hear more about it if you do. Maybe my PC Booster PC-man tape could load on it?
  8. M

    ISA cards with high bus speed tolerances

    I built my own NEC V20HL 16MHz machine (SBC based on Serges Xi8088) with the hopes of clocking it at the full 16MHz but I could only get video stable at about 11MHz with certain VGA cards (TVGA 9000i and an 8900D) and usually with 1 wait states on IO & VRAM read/writes. As it's a novice build I...
  9. M

    Bring XT floppy controller from Compaq Portable back to life

    Tell me about it! It took me ages to get PCjr-esque read-only DMA-less floppy disc support into Sergeys 8088 BIOS code to work in my 'XTjr' homebrew machine. It's just neat that OmniDisk lets you read floppies in a DMA-less mode and doesn't need BIOS support (I think it can use either polling...
  10. M

    Bring XT floppy controller from Compaq Portable back to life

    I don't know about the Sydex utils will add to my list next time I'm fiddling with my floppies. ImageDisk is awesome but I could only get it to work in DMA mode, so I could not use it in my machine and i just wondered if being able to use FDC in non-DMA mode (PIO mode) might help rule DMA issues...
  11. M

    Bring XT floppy controller from Compaq Portable back to life

    Hello not sure this is helpful or not, but I highly recommend the DOS version of OmniDisk. It's got a bit of a learning curve with its CLI but it lets you talk directly to the uPD765-based FDC (I assume that's what the portable uses) without using the BIOS and I've used it a lot for diagnostics...
  12. M

    Compaq Deskpro 386/16 (considered the very first 80386 computer) - deep tech documentation

    I think this is amazing, I'd love a recreation of the Deskpro 386 as I think it was a big step in the PCs dominance and continuation as an open(ish) platform and I think this would be a reproduction possible - esp. as there doesn't seem to be many original machines left...
  13. M

    Missing resistor on Oak Tech 16-bit ISA VGA card, what should it be?

    No worries, I've fixed up a couple of old VGA/EGA cards and quite enjoy looking through the nice pics on VGA Museum to match up boards and try reverse engineer bit on them :) I've heard of other people having 'unstable' cards and the DAC was the issue - my money would be on that. From...
  14. M

    Missing resistor on Oak Tech 16-bit ISA VGA card, what should it be?

    Is it like this card on VGA Museum: https://www.vgamuseum.info/images/palcal/oak/273_1067082021_rev.c_top_hq.jpg (taken from https://www.vgamuseum.info/index.php/cpu/item/325-oak-oti-067)? I'm wondering if it's just a 0 Ohm-ish, jumper-style resister if the Crystal is missing to provide a...
  15. M

    Interesting bugs we have to deal with as system and BIOS developers :)

    That's really interesting thanks for taking the time to share your process. I learnt it's really hard to debug custom BIOS issues, especially when there is no emulator for your system! I went a bit made trying to get PS/2 mouse to work in DOS with only 1 PIC and getting the floppy drive to...
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