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Proposition for all Sega CD owners.

Discussion in 'General Sega Discussion' started by SegaLoco, Jun 25, 2009.

  1. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    And wondermega uses some other CDC, the only Sanyo chip is a LC8951, there are more chips on the 2nd board: HD4074019FS, CDX2500A0 and CXA13720.... Wondermega is a bitch setup since the board is covered with noon transparent stuff on one side and all research is severly complicated :/
    ...and Wondermega uses same OTP EPROM chips as Xeye BTW

    The FFFF/FD0C this is interesting.... I'll do some more overdumping.... this is fun... today is busy day, I haven't got around to sleeping....
    Shadowing should not be the case in my dumps since MCD is in inactive state and I did dumps of the chips themselves (but I cannot be sure that I actually compared the file off the chip not the file off the cable........... I'll be sure today when I do more fun). I'm seriously going to do a nice facepalm when the case in ( ) is true.....
     
  2. Sik

    Sik

    Sik is pronounced as "seek", not as "sick". Tech Member
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    being an asshole =P
    What if there are two different revisions but are so minimalistic that the version number wasn't changed at all? =P

    *slapped*

    :(
     
  3. SpinelSun

    SpinelSun

    Oldbie
    So the wondermega uses the same Toshiba TC531024F-12? (you said TC531024F-120.. ) Yours is the SEGA Wondermega right? Not the Victor one? If its SEGA, did the Wondermega mainboard contain SEGA or Victor markings? and did the BIOS ROM in the wondermega have a label with a SEGA MPR or OPR part number?
    the Sega CD 1 uses the LC8951, Sega CD2 use LC89515 which are both compatible IIRC but the LC89513K is not 100% compatible with LC8951 IIRC... but I could be wrong.

    Alright cool. I await your results.
    Because I have Personally dumped my Sega CD 2 (2.11X BIOS) with a ROM reader and ROM contents at 0x72 had FD0C and main memory copy had FFFF overlay (mirror overdump had FD0C also). Also the guy from gamesx dumped his 1.02 US and 1.02 JP Laseractive SEGA PAC BIOS chips directly with a ROM reader and his dumps have FD0C, same with the person who dumped the 1.04 US laseractive, FD0C.

    Also, the first byte in your dumps (0x00) have F4FF, but chip dumps have FFFF. Main memory shadow overlay copy AND mirror overdump copies both have FFFF. could there be a bug in your dump program? Because I have never seen F4FF at 0x00 in memory or chip dumps...
     
  4. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    The change is about a thing that is "don't care".... all other bytes are same in the dumps.
     
  5. SpinelSun

    SpinelSun

    Oldbie
    Not quite sure I understand...

    I think what you're trying to say is that the bytes that are different between mine and your dumps, don't matter at all, it will work fine with "wrong" data there, right? I know that already :)

    However I am an extreme perfectionist. When dumping something, I should be exactly sure that the data is 1:1 whats on the chip, if it's being dumped from memory. Which is why dumping the chip directly is preferable, if it all possible.
     
  6. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    I just pointed that out to Sik, I myself am a bit perfectionistic too and I'm going to find out if my dumps are good or not.... and it seems I'm not going to bed today anyway....
    direct dumping is always possible, you just need some equipment and de/soldering skills and I've got all of it :3

    EDIT: I just redumped all the BIOSes, this time the whole range they're mirrored in, and they all had $FFFFFFFF in the shadowed vector part.

    I'll be getting down to desoldering one chip later on, and the MPR for my MCD2s will come in a moment, I forgot to take that piece of paper with me.

    EDIT2 : The BIOS chips in my MCD2s have MPR-15512-T (and 5M62-15-L661) written on them.
     
  7. SpinelSun

    SpinelSun

    Oldbie
    Which Country/bios version did MPR-15512-T come from? both MCD2s had the same BIOS version then?

    and what model was your Wondermega? the Victor RG-M1 or the Sega HWM-5000/HWM-5010?
     
  8. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    The last 0 is always omitted from (Flash(E(P)))ROM chips, 12 means 120ns, which is a normal value.
    The BIOS is a OTP EPROM with no MPR/OPR markings. Same Toshiba chip as in Xeye is used in the Wondermega.
    Only things with Sega markings on the boards are the ASICs or rebraded chips by Sega, all else is JVC. I cannot wait to get a working camera...

    Its getting more fun and fun...anyway, direct chip dumps I will do reveal all wether MCD side is doing fun with certain locations or not.... in my cases, with cable dumps using MD side with cartboot, mirrors had still FFFFFFFF in the vector of interest....
    I need to dig out my heatgun...

    Ok, seems the MCD is not totally inactive or something, the mirrors have the first bytes FF not F4...... fun stuff...

    bug is highly unlikely, since the programs that do dumps are not doing any real data manipulation other tan splitting a byte into nibbles, I just read a byte from $400000 and send it to PC which will store it, and the process repeats until desired amount it read...


    MCD2s are both European ones, BIOS ver 2.00 , Wondermega is a Sega HWM-5010.


    And here's the cable overdumps : http://www.fileden.com/files/2008/4/21/1876835/BIOSES.RAR

    I'm starting to think that dumps from MCD using MD side won't be that effective.... now I'm wondering what happens if I put couple of dummy send/recives into the programs.... data corruption is highly unlikely, I use same routines in one other program that cannot work with data corruption and it works perfectly...
     
  9. SpinelSun

    SpinelSun

    Oldbie
    Just to confirm, both of your MCD2s have the same 2.00 with the same MPR-15512-T number? Your original post made it sound like both of your MCD2s each had a different version BIOS?

    Yeah, it just could be that reading the shadow address bios location will always read as FFFF in all mirror locations when the sega cd is completely off/disabled. Cause when the Sega CD is powered on/enabled main reads FFFF and mirror reads FD0C, and FD0C is what's been shown to be in the physical ROM.
     
  10. SegaLoco

    SegaLoco

    W)(at did you say? Banned
  11. SpinelSun

    SpinelSun

    Oldbie
    no. Those are overdumps done with his genesis side dumping program to show me what he is seeing.
    In all likelyhood, my original dump was good. But in anycase, Tiido will be desoldering the BIOS ROMs and dumping them directly so we'll know exactly whats on the chip. So, wait abit.
     
  12. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    http://www.fileden.com/files/2008/4/21/1876835/XEYE-G304.BIN

    This is the chip dump of the Xeye BIOS, and the chip IS as mask ROM, and there seems to be some "serial number" too, Xeye has G304, Wondermega has G301.

    And seems when I did my first chip dumps last year, things somehow got mixed up or something... and I can safely say that bumping MCD BIOSes from MD side off a cart is not a good idea, since the vector gets shadowed with FFFF... it is fun that whole address range has it FFFF...

    so it seems your dump was good afterall :)


    I'll be chipdumping Wondermega BIOS too in some moments when I start soldering adaptor wires to it.
     
  13. Revival

    Revival

    The AppleTalk Network System Member
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    I'm picking up a Mega-CD soon, I'll be sure to dump the BIOS. Just one I'm nabbing from eBay.

    @those who don't have a parallel port: How the hell can you not have LPT? Your computer must be one of those NetBooks.
     
  14. Sik

    Sik

    Sik is pronounced as "seek", not as "sick". Tech Member
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    being an asshole =P
    Most new computer lack a parallel port. All new devices are pretty much either using USB or are wireless, so by this point supporting the parallel port seems useless for manufacturers. Some motherboards have the connections internally, just not the plugs, though some truly have it removed.

    So, yeah, you need to get an old computer to have a parallel port these days =/
     
  15. SpinelSun

    SpinelSun

    Oldbie
    Awesome! Good to know my original dump was good afterall!
     
  16. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
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    T-04YBSC-A !
    Wondermega BIOS chipdump :

    http://www.fileden.com/files/2008/4/21/187...ERMEGA-G301.BIN

    some pics of dumping gear :

    [​IMG]
    [​IMG]

    I would do my MCD2 BIOS dumps too, but I am not able to get the chip out without more major effort.... I will try one trick though, since I know what the ROM has to be... (relates to forcibly disabling some chips in MCD.....).
     
  17. SpinelSun

    SpinelSun

    Oldbie
    Nice!
     
  18. NTICompass

    NTICompass

    Slamma Lamma Ding Dong Member
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    I have a SegaCD. It's a US version 2.00. I've bought all the parts necessary to dump the BIOS. I should have that to you by the end of the week, that is if the mail is on time.

    EDIT: Got the cable created. All I need is the PCMCIA parallel port I bought.
     
  19. SegaLoco

    SegaLoco

    W)(at did you say? Banned
  20. SpinelSun

    SpinelSun

    Oldbie
    The person who dumped that multimega dumped a X'eye, and his X'eye had 290f8e33 as the crc32? you sure?

    Because this Multi-Mega dump looks to have two bad bytes in the vector table. At 0x72 is FFFF. So this looks like they dumped it with Mask of Destiny's cable and software. So far ALL Mega-CD/Sega-CD/CD2/CDX/X'eye/Wondermega/ Pioneer PAC-S1 and PAC-S10 have FD0C at that location.

    There is trick to get 100% good BIOS dumps from MoDs software by overdumping the BIOS, I believe I mentioned it in this thred already.

    Just a FYI, list of good dump bios crc32s, your files might be named different

    290f8e33 us_xeye_931227.bin
    d48c44b5 us_scdx_930907.bin
    2e49d72c us_scd2_930621.bin
    9f6f6276 us_scd2_930601.bin
    8af65f58 us_scd2_930314.bin
    c6d10268 us_scd1_921011.bin
    50cd3d23 us_mld_930922.bin
    3b10cf41 us_mld_930329.bin
    d21fe71d jp_swm1_920206.bin
    00eedb3a jp_mld_930329.bin
    dd6cc972 jp_mcd2_921222.bin
    550f30bb jp_mcd1_911228.bin
    9d2da8f2 jp_mcd1_911217.bin
    4d5cb8da eu_mcd2_930601.bin
    0507b590 eu_mcd2_930330.bin
    529ac15a eu_mcd1_921027.bin

    bad dump, 0x72 in ROM has FFFF shadowed there
    34d3cce1 eu_mm_930916_x.bin

    most likey the good dump, but not confirmed with a redump, I just hexed the two bytes to what they most likely should be.
    aacb851e eu_mm_930916_fixed.bin