Sega Saturn Region Free BIOS

Discussion in 'Sega Saturn Programming and Development' started by Serantes, Jun 12, 2011.

  1. APE

    APE Site Supporter 2015

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    Yep, thar be an SH-2 in them Saturns. Amongst other processors...
     
  2. Druidic teacher

    Druidic teacher Officer at Arms

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  3. Bad_Ad84

    Bad_Ad84 The Tick

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    Well, this thread about is bios modding. Id imagine the bios code runs on the main CPU which initializes the rest of the system. So SH-2 support is all thats needed in the context of this thread.
     
  4. Druidic teacher

    Druidic teacher Officer at Arms

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  5. l_oliveira

    l_oliveira Officer at Arms

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    Perhaps it's for the PITCH and Karaoke functions on the CD player ?:shrug:
     
  6. Druidic teacher

    Druidic teacher Officer at Arms

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  7. Bad_Ad84

    Bad_Ad84 The Tick

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    Yeah, but the bios code doesn't "run" on the SCU - its playing an animation, but the actual instructions in are ran on the SH-2, which is supported by IDA pro - therefore accessible for people to hack.
     
  8. Runik

    Runik Member

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    Nope.
    It's used to copy the boot music data to the VDP1 ram (don't ask me why they did it that way :shrug:)
     
  9. grips03

    grips03 Rising Member

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    DathCloud, Any trick to flashing MX29F800TMC-90 with Sega Saturn BIOS v1.01 (multinorm).bin?

    thanks
     
  10. Bad_Ad84

    Bad_Ad84 The Tick

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    Its a 8/16 chip so directly programming the file should be fine.

    Its mentioned to byte swap it on a 16bit chip, which that isnt.
     
    Last edited: Jul 3, 2011
  11. DarthCloud

    DarthCloud Fiery Member

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    Since most programmer write those flash chip in 8bit mode you need to first swap the bytes of the file using something like hex workshop (called byte flip in that program I think) (some programmer software might have a byte swap option too)

    After that since this chip is 2x larger than the BIOS binary you can mirror the bios on both half of the flash chip.

    In windows you can open a command prompt and do the following:

    copy /b ssbios_bs.bin+ssbios_bs.bin ssbios_bs_1mb.bin

    Then you can program that 1MB file on the flash chip.

    I used a willem eprom programmer with the SSOP44 adapter. You can get those for rather cheap.

    This flash chip support both 8bit and 16bit addressing mode. The Saturn use the 16bit mode with Big Endian. Since most programmer use 8bit mode to program those chip you need to byte swap the binary before programming.
     
  12. Bad_Ad84

    Bad_Ad84 The Tick

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    I was just going off this:

    the 27c800 is 8/16 too, but he only said to swap on 16 only chip.

    either way, if what you said works then ill do that.
     
  13. DarthCloud

    DarthCloud Fiery Member

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    Ok I guess d4s instruction are a bit unclear. This will only work with a chip in 16bit mode. 8bit will not work. Saturn bus is 16bit big endian.
     
    Last edited: Jul 3, 2011
  14. Bad_Ad84

    Bad_Ad84 The Tick

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    That makes much more sense than how I read d4s' instructions.

    I see now that he basically meant "Use a 16bit eprom and byte swap it", just didnt read like that to me.

    Thanks
     
  15. Segata Sanshiro

    Segata Sanshiro speedlolita

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    I don't suppose this will auto switch between 50/60hz?

    Tempted to do this to a model 1 PAL Saturn..
     
  16. grips03

    grips03 Rising Member

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    from what I have read it won't switch 50/60Hz, still need a switch for that.
     
  17. grips03

    grips03 Rising Member

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    DarthCloud,
    You don't happen to have a link to the willem programmer you used for the Saturn and Dreamcast do you?

    thanks
     
  18. Bad_Ad84

    Bad_Ad84 The Tick

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    www.mcumall.com

    This is the programmer I used to have, but its better than the normal para willems (faster, usb not para) and uses the same adapters.

    I can recommend them for the price.
     
  19. Segata Sanshiro

    Segata Sanshiro speedlolita

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    Bad_Ad84, any chance you could sell me a chip or two should I require one? :)
     
  20. DarthCloud

    DarthCloud Fiery Member

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    Yeais use one of those usb programmer. LPT like mine are annoying to use now with recent computer.
     

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