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N64 up and running

N64 adapter Mess o'wires Voltage hack


News from the N64 front: all of my carts are now playing. The whole thing went rather smoothly, took me just a few hours for adapter build and firmware implementation… Unlike other systems, the ROM access scheme of the N64 library appears pretty uniform. So far, no trouble with weird bank switching or hidden memory areas whatsoever. Title, ID (instead of checksum) and size detection also seem to work reliably. The loading times may appear unusually long, but considering the massive amount of data, it’s really not that bad. Mario 64 (8MB) takes about 30 seconds to load.

As usual, my plug-in adapter is just a bunch of wires, but in practice we will have to translate between the Retrode’s 5V and the N64’s 3.3V. For now, I solved the issue by sacrificing an old prototype and regulating the entire circuit down to 3.3V. I plan to put up a reference adapter design for 5V Retrodes in the next few days.

Title                    ID    Mbyte
Chameleon Twist          NCTP   12
F1 World Grand Prix      NFWD   12
NBA Pro 98               NBAP   12
Super Mario 64           NSMP    8

While we’re at it, here’s a quick list of things that will be included in the next firmware version:

  • SNES mouse support
  • N64 plug-in adapter support
  • Virtual Boy plug-in adapter support
  • Config parameter: cartridge detection lag

26 comments to N64 up and running

  • Alex

    Man, I really want a Retrode but now I want to get one of these too and don’t want to pay 2x shipping :( Judging from the A2600 adapters this may take awhile to release, no offense intended I realize you have an actual life outside of the Retrode too, school I believe. I guess I could try making my own, and probably fry my Retrode in the process.

    • Actually, I haven’t worked on the 2600 in ages, since N64 is just so much more fun with every regard. Right now, there remain a few open questions, most importantly where to get the card edge connectors. I do not want to order 200pcs, since there is NO WAY I will ever sell that many 2600 adapters.

      As for the N64 plug-in, I hope to get the final proto running by the end of next week (including the GBs!), at which point it will be all about ordering the parts. Again, it’s the large quantities that give me a bit of a headache, but that can be figured out.

  • Ness and Sonic

    Expansion pak games (DK64 and Majora’s Mask) are the true test of an N64 adapter. If it can support that it truly something to take seriously. The problem is I am not sure if there any emulators that support those games.

  • kakashi

    N64 cart pin 6 and pin 31 is GND or not?

  • [FelixV]

    how do you decide if the adapter will work on the mega drive or the snes side ?
    the n64 goes in mega drive but the 2600 goes in the snes slot is why i am asking.

    • Ease of firmware implementation. N64/GBA/VB have 16-bit data buses, while 2600/NES/SMS only have 8 data bits. Also, if you are using a N64 adapter on your Retrode, you are most likely a Nintendo fan, so we can safely block the Sega slot :)

  • Robert

    Great work Matthias :)

    Is there any chance you would ever consider supporting the on-cartridge saves? I realize there are four types which make it more complicated, but I think it would be fantastic to at least be able to backup the 256Kbit SRAM saves, since once the cart battery dies the saves will be lost (and most of the N64 cart batteries are already well past their expiry date)

    I would just really like to backup my Zelda Ocarina of Time and Super Smash Bros saves before they disappear…

    • > Is there any chance you would ever consider supporting the on-cartridge saves?

      Who, me? :) Not very likely, but who knows what might happen once more people start hacking the Retrode…

      • Robert

        Thanks for your reply Matthias. Just one more question if you dont mind – will the N64 adaptor hardware already be wired to support on-cartridge saves, or will it need to be modded first? (Like the Sonic 2 mod)

        • The N64 adapter does not support on-cartridge saves. I do not plan to support them because I simply do not have the time nor slightest motivation to understand and implement the zillion different savegame schemes of the N64 (SRAM, EEPROM, etc). Sorry!

  • Bry

    If Super Mario 64 takes 30 seconds, and if the load time scales linearly, we could expect 64 MB games (like Conker’s Bad Fur Day) to take 4 minutes.

    …not that it would stop me from wanting to buy such an adapter, of course. The prices suggested so far seem reasonable enough.

    Any thoughts on also working on a Controller Pak adapter? Probably not worth the effort (handling on-cartridge saves would be much more useful), but it would be neat nonetheless.

    • Yes, the slow connection is just perfect for 16-bit games but once it gets more data-intense, it takes forever to load. I told you so, and I cannot stress enough that N64 is a bonus feature only. Developing with High-speed USB capable microcontrollers is out of reach for hobbyists like me.

      Since I have limited time to spend on the Retrode, I will not support any fancy N64 extras, nor on-cartridge saves of which there are at least 4 different technical implementations to my knowledge. Let us leave that up to future generations of Retrode hackers :)

  • [FelixV]

    I would also pay 15 EUR each also. Keep up the good work Matthias

  • Matt B

    Would it at be at all possible to integrate all these adapters together eventually? So instead of releasign an n64 adapter, gba, nes, virtual boy and atari adapters. Maybe you could combine them all on one board? Then you could charge $40 – $50 for one adapter instead of $20 – $30 per adapter. Then there is always the idea of the retrode 2……

    • Lots of reasons to do one thing at a time. :)

      0. By doing these adapters, I want to showcase the potential of the Retrode and the simplicity of adding new functions. This is clearly “bonus”, the main product will always be the Retrode itself.
      1. Manufacturing these things means ordering sh*tloads of parts that don’t come cheap. Just to give an example, GB connectors have a minimum order quantity 1K pcs and a lead time of several months. As long as I’m in the red with the Retrode main unit, I don’t feel like spending money like that.
      2. I prefer simple, fast, and reliable solutions over ridiculously huge boards with tons of carts dangling from all sides. Plus, having all carts on the same bus and keeping them from talking to each other seems like the worst nightmare. The Retrode has two slots, and that’s as much as I want to handle.
      3. My advisor just gave me a broad hint that he’d really appreciate me finishing my thesis. I feel that with all this Retrode stuff, I’ve already stretched his patience quite a bit.

  • Will you be making these adapters in bulk for sale or will they all be DIY projects if we wanted to have one for ourselves?

    Love my Retrode!

    • Luke Johnson

      I keep asking him this…with no reply so I’m guessing he’s trying to see if that’s feasable. If he makes them, I’ll buy one – if not….I might just have to get down and dirty.

    • I’d really love to provide adapters of good quality, but in these small numbers they won’t come too cheap. With professional (Chinese) PCB manufacturing they will probably end up at EUR 15 each.

      • Luke Johnson

        I would definitely pay $30 US for a preassembled N64 adapter.

      • agaiz

        Sounds like a fair price… especially when I consider the prices for N64 games on Virtual Console (8-10 Euros). So I’d buy one too!

      • Christoph.Krn

        Personally, I’d even pay 30€ for an assembled N64 adapter. 15€ is a reasonable price really, even if the parts alone don’t justify that cost. I’m very sure there would be enough people willing to buy an N64 adapter for that price.

      • Luke Johnson

        I should add that my buddy would buy one for $30 as well (though he doesn’t have a retrode…yet)

  • Jesse Vaitkus

    Damn man you just don’t quit! Good work!