DCHDMI

Discussion in 'Sega Dreamcast Development and Research' started by psydefx, Apr 4, 2018.

  1. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    That's great. I like your style my friend.
     
  2. Xerxes3rd

    Xerxes3rd Rapidly Rising Member

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    The whole project is really well-done! Can I ask where you're getting the custom flex cables? They've always seemed interesting but I don't know where to get them manufactured.
     
  3. citrus3000psi

    citrus3000psi Housekeeping, you want towel?

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    The place I've been using is PCBWay. There are many places, but they are the cheapest I found. Base price starts at $100, which sucks. You want to get it right the first time. I spent quite a bit of time reading up on flex cable design before sending my first order in.
     
  4. maxtherabbit

    maxtherabbit Member

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    So what was the reason for going to the FFC? Are you doing that instead of the QSB + ribbon cable?
     
  5. Xerxes3rd

    Xerxes3rd Rapidly Rising Member

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    Wow, yeah, that's not something you want to make too many mistakes on! Once you complete/release the DC HDMI project, it'd be awesome to have a summary of (or notes on) your flex cable design process.
     
  6. citrus3000psi

    citrus3000psi Housekeeping, you want towel?

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    To do the FR4 QSB, you have to do an advanced PCB fab service to get castellated holes that small. Which ends up being more expensive than the flex cable. Oshpark is hit or miss with castellated holes this small. And the flex cable is still much easier to install.
     
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  7. MastaG

    MastaG Member

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    Hi citrus3000psi.. any update on this?
    I'd really like to install one in my Dreamcast :)
     
  8. citrus3000psi

    citrus3000psi Housekeeping, you want towel?

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    We are currently trying to figure out some interference issues. Its sporadic and seems to be related to the board design. We are switching to a 4 layer design that will isolate data signals better.
     
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  9. MastaG

    MastaG Member

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    thank you for the update.. can't wait to order one.
     
  10. MastaG

    MastaG Member

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    Btw, will it be something like a complete kit with a QSB and a breakout pcb with a female hdmi socket?
    Perhaps you can share some pics, to ease up the waiting :p
     
  11. citrus3000psi

    citrus3000psi Housekeeping, you want towel?

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    There is a flex cable that connects up to the DAC and audio processor
    [​IMG]

    The flex goes to the bottom side of the motherboard and hooks up the main PCB.

    [​IMG]
     
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  12. fafadou

    fafadou Peppy Member

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    Really impressive !
    But I have a doubt, you take the audio and video signal before the "RCA and/or VGA" conversion ? That is called "hdmi native" ?

    anyway this board is amazing !!
     
  13. maxtherabbit

    maxtherabbit Member

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    hes getting the signals from the inputs of the Digital to Analog Converter, so yes before conversion
     
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  14. chriz2600

    chriz2600 Newly Registered

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    Just to clarify and confirm, no analog to digital conversion is done on the DCHDMI, the video and audio signals remain in the digital domain.

    For more details, check:
    https://github.com/chriz2600/DreamcastHDMI
    https://github.com/citrus3000psi/DCHDMI-Hardware

    Dreamcast is sending the 24 bit (digital) RGB values in two 12 bit chunks at a double clock rate, the FPGA converts this to 24 bit with standard clock rates. It also recodes the 480p signal to a real VGA signal (for proper aspect and pixel ratio) and also does the recoding to 960p and 1080p. The (digital) I2S audio is passed directly to the HDMI transmitter.
     
    Last edited: Jun 14, 2018 at 4:07 PM
  15. fafadou

    fafadou Peppy Member

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    Whaouh ! Unbelievable !
    Well done, I am very exciting now :)
     
  16. Treamcaster

    Treamcaster Intrepid Member

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    Can't wait for this, amazing job guys...
     
  17. MastaG

    MastaG Member

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    Yes chriz2600, I'm checking out your github repository almost daily ;)

    Keep it up guys. And please when the interference issues are solved. Make sure to produce enough units so we can all buy one.

    Cant wait for this.
     
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  18. Marmotta

    Marmotta Dauntless Member

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    Looking fantastic. This is the most excited I've been for any console mod yet.
     

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