nesdev.com

Now that the HDMI project is in the bag and mostly thru production, I was wondering about a next project and had the idea for a really nifty flash cartridge.

Yes, there's two on the market right now (Power Pak and the Everdrive) but I was thinking of making my own to address the shortcomings of both, and to make it do just that little bit more.

So the bullet points would be:

* Full mapper support - including MMC5, mapper 90, etc
* Full expansion audio support like the HDMI adapter
* 1/8" stereo jack on the end of the cartridge that allows you access to line out stereo audio - no system mod required
* Audio would also exit in mono form on the usual pin for those that want an audio mod
* Digital audio is possible, since it will use a DAC so spdif and similar would be a theoretical option
* Gameboy support - ability to play GB ROMs natively on the cart with the NES outputting audio/video for the game
* SD card running in 4 bit mode for instant game loads
* Save states on select mappers (i.e. MMC1, MMC3, etc)
* Game Genie support of course
* USB to download code to test instantly
* High resolution menus using a 5 pixel high variable width font
* Low resolution menus using a 7 pixel high variable width font
* NSF playing with visualizer
* GB link port - you would have to transplant an existing GB link connector though
* CopyNES lite

There's probably a lot more dodads and geegaws I could add that I can't think of at the moment.

I figured since the existing flash carts on the market don't really do everything I want them to do and the odds of them being able to do so is slim to none, a new flash cart might be in order.

I have all the mappers done already on the FPGA NES so the mapper thing isn't a problem, and the FPGA gameboy is done also, so getting it to play GB games is not a problem either. For the variable width fonts and 5 pixel high text mode, I was going to have a CPU on the FPGA handle most of the menu stuff, with the NES merely acting as the output device. This frees me from all the vagaries of the NES graphics restrictions like waiting for vblank, and even the notion of tiles is completely made irrelevant. I can easily produce a full bit mapped NES display on the FPGA with it handling all the dirty pixel -> character translation, and I can even do 8 attribute changes per character.

So, what do people think about this type of thing? I am not sure if there is a market with the existing carts out there, but the complete(ish) mapper support and gameboy playing might push it over the edge. Cost would be in the $120-150 range probably.

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Sounds cool! The Game Boy part is really interesting, and together with support for mappers that have been overlooked will surely guarantee a decent number of sales. I know I'm interested, and I already own the 2 existing flash carts.

It's a shame the NES can't do Game Boy Color graphics, because I'd really like to play that on the TV, and there's no way I'd buy a Game Cube + GB Player (shitty optical drive with moving parts that's bound to fail) just for that.

Yeah my GB core does do GBC right now. You'd only be able to play in 4 level greyscale unfortunately so that's why I wouldn't include it.

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You could try running SMS and GBC games in "slivervision". It's not perfect, but it's at least better than "GBC ONLY" error messages.

• Set a constant palette 0F001020 0F172720 0F112120 plus a fourth possibly used for the UI.
• Output GBC games' graphics in 4-level grayscale, possibly with some sort of Bayer dithering.
• For each 8x1 pixel sliver, calculate the sliver's average chroma, test whether it's closer to gray, orange, or teal, and output that as the attribute. You can do this by calculating I from YIQ or Co from YCgCo. Co in particular is just R - B.

Put in slivervision for SMS and GBC, and I just might buy one.

FDS support?

Ability to customize menu?

Ability to add or customize mappers?

I am definitely interested despite already having an EDN8. I'd love to have a cart that actually supports MMC5 and the VRC's properly, and the GB feature sounds fantastic.

Would it be possible to make a famicom version? I'd buy a NES one, but it'd be nice to have it not triple the height of my famicom. :p

Please do include it! I'd love to be able to play GBC on the NES, even if it's in grayscale! If you think people will think less of your device because the GBC games don't look good, you can maybe leave this feature disabled by default, and display a warning about the color limitations when it's enabled.


Now you got me all excited about this. Man, playing SMS games on the NES would be awesome! Every FPGA console you can fit in there will make this cartridge even more awesome. It's really cool how having the VRAM bus available to the cartridge makes it simple to stream video at full speed, even if the colors are far from perfect. Can you imagine being able to play PC Engine/TG-16 games on the NES? That would be insanely cool, specially considering that not many people played it back in the day, and it's not a console that's easy/cheap to come by (except in Japan).


Definitely... the more consoles you include, the more I'll want to buy one.

I'm not so sure about the orange/teal suggestion, though... tepples, would you mind mocking up a screen with the algorithm you described? Scrolling would greatly affect the results, because the attributes would appear to "jump" in 8-pixel increments, which could be really distracting. This sort of color clash was extremely unpleasant on the Spectrum, and I'm afraid it would be in this case too.

I would definitly buy one in an heartbeat. If It can support bigger ROM than PP and EDN8 that's all the convincing I need but I got to admit the rest of the festure soubd pretty awesome even If I doubt I would use most of them.

Exactly one week ago I was musing over at the NintendoAge forum about the Ultimate NES/Famicom Flashcart, which pretty much boiled down to complaints about what is wrong with each of the existing carts.

I would hope it could support 2MB of PRG-ROM for FFVII or Action 52. (Neither are my cup of tea, but if you want some advertising features...) If you will be supporting all non-Color exclusive Game Boy games, including the hybrids, you will need to support 2MB and 4MB games.

How exactly would CopyNES lite work? Would you have to remove the flash cart and insert the cart you wanted to copy?

What about Pro Action Replay code support? I don't think anyone has ever attempted that.

Could the Game Boy core emulate the sound effects and the palettes of the Super Game Boy? I know that the borders are not possible due to the NES color limitations, but the rest should be possible, maybe.

I assume that this will be completely compatible with the HiDefNES mod and can think of no reason why it shouldn't be compatible with NESRGB. But with native video, the PowerPak adds noticeable jailbars and even the Everdrive is not immune from enhancing the jailbars a bit compared to licensed cartridges. Can your cart do at least as well as the Everdrive?

There is definitely interest.

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How feasible is it to implement debugging features on a flash cart (or is that what you mean by CopyNES light?)?. For example -- bank watching, stepping debugger, read/write/exec breakpoints, instruction trace logging, RAM listings -- all on real hardware, using a gdb-like textual control interface over USB. I think these kinds of things are possible with CopyNES, but it would be amazing to get them from a cart instead.

I'd be very interested! Let me know however I can help

I'm interested.

Those are the colors that are perceptually farthest apart. The human visual system has a lot easier time telling small areas of teal from orange than telling green from purple.


That could take a while, possibly a few pages of this discussion before I get to it.


Not if he aligns the tile grid by feeding fine scroll values from the cart through $2005. He's already planning to feed audio through $4011 every hblank, and he said in #nesdev that he could feed fine scroll at the same time. Edges of sprites would be most affected.


Unpleasant is still better than "This game works only on Game Boy Color".

100% would buy. I was looking into the EDN8, but after seeing your (at least I think it was you) comments in another thread about how their mappers are all coded asynchronous and all the issues people are dealing with as a result, I would love to see a cart with the mappers implemented properly, and the GB support would just be that much more of a nice touch. Would you consider FDS support as well?

These are all nice features. The ones I'd be most interested in personally are 1MB PRG ROM (and 4k banking that doesn't half the PRG size), and I guess VRC7 support. Both of these are somewhat minor to me, though.


My main complaint with the PowerPak is a complete lack of ongoing official mapper support. The mappers haven't been updated since 2010. Loopy made some important unofficial additions, and TheFox more recently made some of his own, at least, but there's no real acknowledgement from RetroUSB.

The Everdrive at least has ongoing support, and it actually has forums and relatively good customer response. Its main drawback is that it its software isn't as far along as PowerPak is, and the hardware seems to be no better (and in some cases it may be inferior).

What I'd really like to see (for any/all of these) is open source mappers, and a support forum. To make a minor change to an existing mapper now, we have to write the whole mapper again from scratch. It would be great if users could review the mapper code, suggest/try and share changes, and have them officially adopted if viable.

Whether you, as the developer would be interested in open source mappers is your own decision of course. There are plenty of reasons to remain closed. I'm just saying that from my viewpoint it's a huge asset to the product.