"Let's make GD ROM emulation happen" Facebook group.

Discussion in 'Sega Dreamcast Development and Research' started by sonicdude10, Jun 18, 2012.

  1. Evotistical

    Evotistical Robust Member

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    Good enough for me :)
     
  2. cybdyn

    cybdyn Embedded developer (MCU & FPGA)

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    now i'm working on CDDA support (on DCIO).
    it works, but with little bad noise. maybe i should use stable freq. ~33.8688 Mhz. w/ CDDA sound it fells more natural)).
    g1-ide adv will be w/ cdda support too.
     
  3. petterk

    petterk Spirited Member

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    How is the speed of the hdd when using g1-ata cybdyn?
     
  4. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    Swat told me he reached 3MB/s (20x) in PIO mode and that it should be possible to reach ~10MBs in DMA mode (70x).

    For comparison, gd-rom are read at 12x and cd-r at 4x by the dreamcast.
     
    Last edited: Jun 13, 2014
  5. petterk

    petterk Spirited Member

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    Awesome! I just watched a video of Sonic Adventure ran through the G1-ATA and it looked like there were slowdowns, but that may be other issues.
     
  6. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    I had somehow missed this post!

    If you can make g1-ide adv with CDDA it'd be AWESOME.
     
  7. cybdyn

    cybdyn Embedded developer (MCU & FPGA)

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    i reached on DCIO max speed of SD ~ 10..12Mb/s <- it's real speed, what i see on osciloscpe!
    hdd is more faster, than SD. i can't say what exactly yet. but you know, you can copy files on pc , and speed can be ~ 40..55Mb/s. maybe more w/ modern HDD))

    but! most things depends on how code of game use gd-drive.
    in some games it reads data by 1 sector, then parse it, then read next one. so it really doesn't matter what speed you have. that's why SD-mod is not bad))
     
  8. polyfusion

    polyfusion Member

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    How would compact flash compare with HDD and GD-ROM? Not as fast as HDD, but still much faster than GD-ROM?

    I don't know much about CF, but I'm leaning towards it, rather than HDD or SSD via a SATA bridge. I think I'd get all the games I'd need on a 16GB or 32GB CF.

    This is great work BTW, when I first read about it a few days ago, I nearly creamed my pants.
     
  9. BlueCrab

    BlueCrab Member

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    The theoretical maximum of the fastest ATA DMA mode that the Dreamcast supports is about 16.7MByte/sec. KallistiOS' ATA reading code gets about 12.5MByte/sec in my tests with this DMA mode (Multi-Word DMA Mode 2) with a relatively new drive (from about 2005 or so).
     
  10. yzb37859365

    yzb37859365 Spirited Member

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    GDI and CDI all Support CDDA?
     
  11. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    In theory, cdda in a cdi or cdda in a gdi is the same challenge, streaming 2352 bytes per sector instead of 2048 and smoothly enough so that it doesn't make sound skips. The only real difference is the format of the container. I think cybdyn can parse cdi just fine, gdi is pretty straightforward.
     
    Last edited: Jun 13, 2014
  12. unixphreak

    unixphreak Member

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    This might be a stupid question but has anyone thought of a convenient or streamlined way to connect the HDD to the dreamcast? Say maybe with a case similar to the old zip drive or Segakara? Does the G1 connect throught the expansion port? If so that would be a great way to enclose the HDD since the Segakara is not functional anyway.
     
  13. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    I don't know what a segakara is, but G1-IDE-ADV could work without the gd-rom drive so you can simply put it once in the DC along with a hdd and forget about it. I guess there could be a way to hook up the HDD via the opened lid for convenience. The G1 bus is only accessible via the gd-rom port on the motherboard, not from any external connector.
     
  14. unixphreak

    unixphreak Member

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    $_57.JPG $_57.JPG
    $_57.JPG $_57.JPG

    this is the segakara attached to the bottom of the dreamcast. it uses the expansion port that the BBA or modem uses.
     
  15. Helder

    Helder Site Supporter 2014,2015

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    Here is another stupid question, how can anyone find those readily available today? Seems unlikely to get them cheap and they aren't on the same bus as the GD1.
     
  16. polyfusion

    polyfusion Member

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    Personally, I prefer the idea of using compact flash instead of HDD, for a number of reasons

    - Can be powered by the internal power supply; I highly doubt a 3.5" HDD could be powered, and don't know about 2.5", possible I'd say, given it's lower power requirements, but unknown at this stage.

    - 40-pin IDE to CF adaptors are very cheap, I can see one on eBay for less than £2 from China to the UK, and it's intended for a PCI slot backplate on a PC, so has a plate which would facilitate hacking/attaching to the DC case.

    - Also, having a CF slot on the back of the DC can allow you to take the card out if you want to add/delete games, or change cards. If a HDD is internal, it's going to be more difficult to add/delete games (unless someone figures a way to do it through the BBA - or maybe stream games from server through the BBA??).

    - I can imagine CF being a lot easier to replace in the future, if an IDE HDD device fails. Plus, no moving parts with CF, so lower power consumption, lower failure rate (?). Plus 16GB or 32GB would be plenty of capacity for me, I think higher capacity would be wasted on me, and smaller capacity would be older and more likely to fail.

    - It might be possible to mod the GD-ROM daughterboard housing so that the G1-ATA-ADV and CF adaptor can be mounted to it (remove daughterboard of course). Because the daughterboard housing is screwed onto the motherboard housing plate, the whole installation should be stable and secure. Having this original part still inside might also help with the intended design airflow (it's possible that with the temp issues seen with the GDEmu board are due to the now big void, airflow now coming directly from the rear vents to the fan, instead of through all the boards like it should - but this is just theory on my part).

    Does anyone know when we might be able to buy the G1-IDE-ADV? Is it weeks or months away? And is there a waiting list?

    Also, will it be possible for games to save to the HDD or CF? Or will we always be stuck with VMUs? (Does the GDEmu device save game states to SD card?).
     
  17. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    No G1-only device could emulate vmu (without connecting to the controller port in addition to G1, it'd be two devices in the end) though DreamShell or a host program could allow for copying gamesaves from VMU to HDD) and I think states as in emulators is realistically out of the question completely.

    I believe cybdyn plans to make it for standard IDE and make sure it's compatible with adapters for 2.5" IDE/sata and CF/SD. The DC powersupply 5V line is most probably powerful enough to power a 2.5" sata drive but it might require soldering some wires to the PSU pins.

    G1-IDE-ADV is developped by cybdyn alone, with some cooperation/knowledge sharing with Ozone. AFAIK it's far from being marketable and you should not hold your breath until the release. cybdyn hasn't stated how he plan on putting it to market, but I'm pretty sure it'll be posted here once it's ready. Stay alert!
     
    Last edited: Jun 16, 2014
  18. Rocky5

    Rocky5 Site Supporter 2015

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    We need a way to copy our games to the HDD, without having to resort to using the SD mod.

    i suggested to the creator of the GDEmu why not make a ribbon cable that fits over the original GD connector (pins are visible) & the pressure from the connector in its slot would press down & hold it in place, then the board could be mounted under the drive. (Metal shielding removed for more space. Like piggy back on the GD PCB)

    this is would allow us to use the drive or the emu board.

    I don't know if that would work, but no one suggested it so.
     
    Last edited: Jun 16, 2014
  19. darcagn

    darcagn Site Supporter 2013, Site Supporter 2014

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    Oh come on, guys, think outside of the box a little bit.....





    Or, rather... outside of the Dreamcast..... ;) Use eSATA!


    [​IMG]
    [​IMG]
    [​IMG]
     
  20. amiga1200

    amiga1200 Dauntless Member

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    ^^ there's NO WAY any of the sata setup/spdif was plug-n-play, i bet that took some SERIOUS skills. :concern:
    i can imagine what the diagrams are like, and by that, WAY out of my league!
    ...
    as for dumping direct to hdd, i can live without it IF a fully working/polished/USER FRIENDLY hdd spoof (CDDA and all) becomes available, i'll use my PAL-EUR deck for the imaging and the NTSC-U LTD-EDIT trash i have for the spoof. (two dc's)
    ...
    saw the bluetube video you did, BRILLIANT work (if the PVM didn't give you headache) but i'll be downing a packet for a plug-n-play version.
    really don't have the skills, or WILL to attempt the level of modification it took to get that, and what's above.
    ..
    for what it's worth, good stuff all the same, hope it's everything you wished/WORKED for. :smile-new:
    +1
     

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