SD2SNES implements Byuu's MSU1

Discussion in 'Nintendo Game Development' started by derekb, May 17, 2011.

  1. djelaba

    djelaba Benzin !, Site Supporter 2013

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    Ikari is adding uPD77C25 support (DSP), with each variant (DSP 1 to 4), as well as BSX-support, and S-RTC chip.
    But SA-1 and Super FX will never be supported...
     
  2. Greg2600

    Greg2600 Resolute Member

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    Ah, thanks for the info. Those he's doing are only a half dozen games more than the just adding DSP-1 to a PowerPak or Everdrive.
     
  3. derekb

    derekb Well Known Member

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    every bit counts
     
  4. MottZilla

    MottZilla Champion of the Forum

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    This is not true at all. It's no different than making any other "repro" bootleg. You remove the MaskROM and connect a programmable ROM (typically EPROM) and you're done. The only difference is Super FX uses SOIC type MaskROMs which are much smaller and are not as easy to solder and desolder as typical DIP chips. There is no reason "$100 is as low as one could go". That's just a number pulled out of one's ass. Now don't get me wrong, if they want to charge that much for their labor that is fine. But don't act as though it is heart surgery. Star Fox 2 costs maybe as low as $10 to make a bootleg of. The primary cost is the sacrificial Super FX cartridge. If you get that cheap enough, the only other cost is the EPROM or FlashROM which can also be had for very cheap used. That leaves printing up a label which the cost is pretty low for that.

    The fact is if you buy a Star Fox 2 bootleg for $100 you are helping someone make one hell of a profit.

    You're right, different Super FX cartridges have differences in their clock speed and how they are set up. Some cartridges (maybe all) have a register which can switch between 10.5mhz and 21mhz. Some or all may have a particular initial setting or maybe a hard wired one. I'm not entirely sure. I know there is a register related to the clock speed but not if some carts ignore it. Doom is known to run at the higher 21mhz. However if you make Star Fox 2 using it, you will not be able to save data. This is why Stunt Race FX is preferred since it does have SRAM and a battery. Winter Gold I think was only released in PAL regions but I've heard it is similar to Stunt Race FX.

    Really the reason people charge so much for a bootleg of SF2 is because most people lack the skills and experience and those that have the skills and experience to do it probably have better things to do than hock bootlegs.
     
  5. derekb

    derekb Well Known Member

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    well, fwiw it really is pretty involved to wire up the eprom as well, I can solder pretty well but wiring that up is daunting to me
     
  6. MottZilla

    MottZilla Champion of the Forum

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    It's not that hard. It's just tedious and takes some time. And you need to use the correct soldering iron, not some big monster that is overpowered and going to melt everything.
     
  7. Greg2600

    Greg2600 Resolute Member

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    Well, I brought that $100 price up on digitalpress forum and was subsequently knocked for saying it was too high, with several people saying it requires a lot of labor.
     
  8. derekb

    derekb Well Known Member

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    well, if everyone thinks the price is too high maybe someone should step up and produce them for less :p
     
  9. MottZilla

    MottZilla Champion of the Forum

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    Just because people who justify the sale of bootlegs harp on you for saying it costs too much doesn't mean they are right. Like I said, you can ask whatever you want for your labor. But the truth is the parts involved cost a tiny fraction of $100 and I wonder if they have the nerve to charge for shipping at that price?

    Again, you can get an EPROM with StarFox 2 on it for less than $10, maybe just $5. Then you need Doom or Stunt Race FX which you could get for as little as $5. Next you need a soldering iron, desoldering pump or braid or something, wire, and solder. These are not expensive at all and can be used for many other projects. You'll probably want a label, so you'll need paper and a printer, again not exactly expensive.

    So if you want to pay someone something like a rate of $80 an hour for their work go right ahead. It probably doesn't even take them an hour if they have done many of them.
     
  10. l_oliveira

    l_oliveira Officer at Arms

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    When I made my Starfox2 repro cart (for personal use) I used Yoshi's Island as donor cart just because it had battery backed SRAM and SGU2. It even have the proper pads for the bigger RAM chip SF2 requires (I used an 128KB chip instead of 64KB it uses). An minor modification was required (connect A15 for the SRAM address to the GSU2 chip) and I was able to use A16 of the SRAM to create two banks, allowing me to put two games on the cart.

    So, the best cart to make SF2 is not Stunt Race FX (GSU1 with 64KB) but Yoshi's Island (GSU2 but with 32KB SRAM)... :shrug:

    Of course it's easier to use Stunt Race FX, but you will end with an underclocked FX coprocessor... :dammit:
     
    Last edited: Jun 9, 2011
  11. derekb

    derekb Well Known Member

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    If I recall correctly some people replaced the crystal in their stunt race fx cart? I could be mistaken, it was a really lengthy discussion on another forum about ideal carts, if I had the link I'd paste it
     
  12. Teancum

    Teancum Intrepid Member

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    As much as people will complain about the price of a SF2 cart (lol I'm not paying a $100 for one) It doesn't really make any difference until some one sells them for less. You can only buy stuff for the price people are willing to sell for and you can only sell stuff for what people are willing to pay. IF everyone stops buying $100 SF2 carts then either the price will come down or they will disappear.
     
  13. Alchy

    Alchy Illustrious Member

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    Also a lot cheaper. Yoshi's Island is £15 or so on ebay.

    When you say "underclocked FX" do you mean that the game lags if you use a Stunt Race cart? Or that the chip is simply running at a lower clockrate than it should be (which presumably isn't much of an issue)?
     
  14. MottZilla

    MottZilla Champion of the Forum

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    I'm not sure if Stunt Race FX can't do 21mhz mode. From what I've heard it is GSU-1 which SHOULD be capable of 21mhz mode. GSU-2 (Doom, Yoshi's Island) only increases the maximum amount of ROM from 8 to 16 megabits. Star Fox (Mario chip) can't do High Speed 21mhz mode though.

    I haven't tried building my own Star Fox 2 carts on both Doom and Stunt Race FX to try comparing them. It would be something good for someone to make a video of comparing them if there is a difference.
     
  15. derekb

    derekb Well Known Member

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  16. MottZilla

    MottZilla Champion of the Forum

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    Reading through that thread I noticed a bunch of misinformation. For example one person used a term that they thought Star Fox 2 didn't run any better on 'Super FX2' because it wasn't 'using both cores'. This shows a lack of understanding.

    Personally I think people think it's supposed to run smoother thanks to popular emulators like ZSNES not emulating Super FX cache delays which results in games performing better in emulation than on real hardware.

    I did check and the CLSR register ($3039) bit 0 controls the clock rate. 0 = 10.5mhz, 1 = 21mhz. It was not clear whether or not GSU-1 or GSU-2 could both enable 21mhz mode. Someone also mentioned seeing a GSU-2 in a Stunt Race FX cartridge. So it's possible some later produced cartridges switched to the GSU-2 when they stopped producing the GSU-1.
     
  17. derekb

    derekb Well Known Member

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    I believe that thread started around the initial 'lets build starfox carts!' craze, so it kinda had alot of speculation involved from the get-go

    anyone happen to know what setup the main repro maker uses?
     
  18. APE

    APE Site Supporter 2015

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    Winter Gold seemed to be a pretty good starting point but off the top of my head I don't recall why. I'd imagine each repro type has their own personal picks for what they use and reasons as to why.

    Stunt Race FX can be overclocked judging by the fact that I found a Stunt Race FX cart inside a box with tantalum capacitors and a crystal in a Digi-Key bag labeled "Super FX o/c stuffs". At the very least I'm assuming I thought I could give it a shot apparently.
     
  19. link83

    link83 Enthusiastic Member

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    So was Star Fox 2 intended to run with a 10.5mhz or 21mhz clock? It doesn't seem to be clear if it does or not, since it runs fine in both modes.

    I know many Super FX games run with a slightly better framerate on 21mhz, but if the game was not designed to really use 21mhz then there doesn't appear to be that much benefit in using a game with a GSU-2?

    Also there seems to be a lot of confusion about MARIO CHIP 1, GSU-1 and GSU-2, with many people believing that the GSU-2 is a 'Super FX 2', which appears to be a completely made up name which Nintendo never used? Isn't the GSU-2 just a GSU-1 that can address more ROM? and if so might there be a high/low pin on the GSU-1/GSU-2 that can be used to select the default clock rate?
     
    Last edited: Jun 18, 2011
  20. Clad-

    Clad- Active Member

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