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PostPosted: Fri Nov 13, 2015 3:20 am 
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I'd guess byuu's contributions for SNES helps a lot, but Neo Geo... It's expensive just to buy one.

How much accuracy do you loose with programmable logic anyway? I understand it's much faster than emulating hardware in software for a CPU.


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PostPosted: Fri Nov 13, 2015 7:12 am 
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Pokun wrote:
How much accuracy do you loose with programmable logic anyway?

In theory? None. In practice? It all depends on how closely the Verilog approximates the behavior of the original hardware. A Verilog NES clone converted from the Visual 2A03/2C02 netlists should be very, very accurate, except for a few signal timing quirks such as the 33 ns(?) /PRGSEL delay. Then it becomes a matter of finding time in the Visual 6502 volunteers' busy schedules to actually decap, delayer, and photograph the chips so they can be traced out.


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PostPosted: Sat Nov 14, 2015 7:33 am 
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Makes sense, thanks for the explanation!


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PostPosted: Sun Nov 22, 2015 5:30 pm 
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Just a little question: How hard would be to implement an Atari 2600 on this cart?
Don't the NES and the 2600 use the same processor?


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PostPosted: Sun Nov 22, 2015 6:36 pm 
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Each Atari 2600 pixel is 1.5 NES pixels wide. How would you handle that?


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PostPosted: Sun Nov 22, 2015 6:36 pm 
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I don't really see a way to do that; the video format of the 2600 is so different from the NES's ... additionally the NES CPU both 1- runs at 150% the speed and 2- doesn't have the 2600's RDY pin


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PostPosted: Sun Nov 22, 2015 6:41 pm 
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Fisher wrote:
Just a little question: How hard would be to implement an Atari 2600 on this cart?

The difficulty would be stretching the horizontal resolution from 160 to 256 pixels in a way that doesn't look weird, and implementing all the mid-screen palette changes that the 2600 allows. The 2600 also has a bigger master palette than the NES, with 128 colors.

Quote:
Don't the NES and the 2600 use the same processor?

Both are versions of the 6502, so they share the same instruction set, but the NES CPU doesn't have decimal mode and the 2600 CPU is missing some address lines, so they aren't exactly the same. Even if they were exactly the same that wouldn't help at all, because you can't simply run unmodified code directly in the host system, since the memory map, registers, etc. are all different. The CPU would have to be fully simulated in the cart, just like the Z80 of the Master System would.


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PostPosted: Mon Dec 21, 2015 12:01 am 
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Any updates on this project?


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PostPosted: Mon Dec 21, 2015 1:36 am 
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The best way to stay updated on kevtris' projects might be to subscribe to his youtube channel:
https://www.youtube.com/user/kevtris

But no, no recent updates on this or his other FPGA projects.


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PostPosted: Mon Dec 21, 2015 1:17 pm 
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It is quite possible that kevtris has lost interest in this project given the overwhelmingly positive response to his Zimba 3000 console on AtariAge.

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PostPosted: Mon Dec 21, 2015 5:46 pm 
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Great Hierophant wrote:
It is quite possible that kevtris has lost interest in this project given the overwhelmingly positive response to his Zimba 3000 console on AtariAge.


Zimba 3000 was taking priority last time I talked to him but the NES cart is still an active project, even if it's been put to the back burner. I told Kevin I want to use the multicart on the Z-3k :)


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PostPosted: Tue Dec 22, 2015 1:40 am 
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Ya. I'm subscribed to his channel and enjoy watching and learning about his projects. I only subscribed after hearing about the HiDef NES, and it looked like updates for that were sporadic and not necessarily coinciding with the progress of the project.

Either way I'm excited to hear about the progress even if it takes a while. Thanks for the info/feedback.


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PostPosted: Tue Mar 01, 2016 8:25 pm 
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I think I'm going to hold off on buying an Everdrive N8 if this is indeed getting made. Nothing recently on his YouTube channel about this, though, or any confirmation that it will be made at all.


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PostPosted: Sun Oct 09, 2016 12:24 pm 
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Seriously i would buy this sight unseen. Just let me know where to send my money.

Any news this thread is quite old?



kevtris wrote:
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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