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PostPosted: Wed Jul 29, 2015 10:37 am 
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tokumaru wrote:
Well, there's always rgb121
Image

That looks a lot better, actually.


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PostPosted: Wed Jul 29, 2015 1:44 pm 
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tepples wrote:
That looks a lot better, actually.

It's not perfect, but at least everything retains its basic colors. It should look much better when flickering at the proper speed on the actual console. I'm not sure how the flickering should be approached when the source material runs at 60Hz... Drop every other frame? Alternate green and red/blue even though the source frame is different? Get rid of the flickering altogether and don't alternate green and red/blue?

Here's an animation test (no flickering: even scanlines always red/blue, odd scanlines always green):

Attachment:
sonic-chaos-animated.gif
sonic-chaos-animated.gif [ 2.92 MiB | Viewed 1478 times ]

I wouldn't mind being able to choose between that or grayscale if it was possible to do something as cool as playing SMS or GBC on my NES. It's a little stripy (don't people love scanlines? :mrgreen:) and dark, but come on, something's gotta give.


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PostPosted: Wed Jul 29, 2015 1:53 pm 
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tokumaru wrote:
Alternate green and red/blue even though the source frame is different? Get rid of the flickering altogether and don't alternate green and red/blue?
Different source materials probably look good with different dither patterns: temporal or fixed, checkerboard or linear.


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PostPosted: Wed Jul 29, 2015 3:03 pm 
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lidnariq wrote:
Different source materials probably look good with different dither patterns: temporal or fixed, checkerboard or linear.

I have avoided dithering completely in the color reduction steps of these tests, because I think it ends up looking like details or textures that weren't supposed to be there.

For completeness' sake, here's the same animation in undithered grayscale:

Attachment:
sonic-chaos-animated-gray.gif
sonic-chaos-animated-gray.gif [ 2.82 MiB | Viewed 1460 times ]

Except for the tree tops, which blend with the sky, I think it looks quite acceptable.

I'll probably stop with the images now. I think I've already expressed too well how much I'd like to play GBC/SMS/GG on my NES, and how I'd love this new flash cart to include these features, and I also showed how I think the games could be rendered by the limited NES PPU. Now it's up to kevtris to decide whether to make this a reality.

Classic Game Boy is cool and all, but the Super Game Boy already takes care of that. GBC games on the other hand can only be properly played on the big screen if you own a Game Cube, which people who don't care about newer consoles don't. Master System and Game Gear would be awesome to have mainly because they're SEGA's, but the more games, the better.

I'm sure this will be a good flash cart no matter what, but here's hoping it will be as cool (for doing fun things) and versatile (as a development tool) as possible, so that it does indeed become the "ultimate NES flash cart", as opposed to just "yet another one".


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PostPosted: Wed Jul 29, 2015 3:13 pm 
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When I said "dither" I meant the attribute zones, whether it's
Code:
GM     MG          GG     MM
MG <-> GM   -or-   MM <-> GG
or the same patterns without the temporal dithering

Since the SMS is just RGB222, there's only a tiny bit of finesse about how to best convert it to RGB121 anyway.


In a tangentially related note ... how much of a stretch would ColecoVision or any other 2nd/3rd generation console emulation be?


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PostPosted: Thu Jul 30, 2015 1:58 am 
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Wow lots of interest in how to get it to play other systems on the NES. haha. I really do like that rgb121 thing, it is the damnest thing, curious about how that'd look on a bigger screen. I might give it a try on the systems I have to see what it'd look like.

I did try benham colour once and it was... interesting. This is something I read about in a 1960's electronics magazine. The idea was to be able to transmit full colour video using just a black and white TV. It exploits the human vision system, but it flickers really bad. I did get it to work but the colours were fairly pale to me... but there.

The trick is a 6 frame cycle; the monochrome output is on for 1, 2, or 3 frames then there's 3 black frames from what I recall. If anyone's interested I can look it up. The NES could natively generate this type of thing for testing purposes.

Apparently some TV ads were made in this format and broadcast but it didn't last very long.

To clear up a few things...

There would only be a single FPGA on the cartridge, due to cost concerns, which makes it a lot harder to reconfigure it on the fly. I was expecting a single configuration. This is why I can't easily let people make their own mappers; the mappers are just a smallish portion of the FPGA code. There's going to be some kind of DRAM controller, SD controller, memory controllers, another CPU, audio hardware, video control hardware, and then the mappers.

When the FPGA is being reconfigured, the NES cannot access any memory on the cartridge (or hardware things like timers, etc) which means there has to be some kind of hardware on the cartridge besides the FPGA so the CPU doesn't crash during the loading. The powerpak uses some TTL logic on the cart to keep the NES happy while it boots, and the everdrive uses a CPLD.

I kind of wanted the SD card connected up to the FPGA so it could load RAM that way; it'd be so much faster and simpler if it didn't have to pass through the CPU; especially for 4Mbyte and bigger ROMs. If I have to pull configurations off the SD card it will need something to do that- either the NES CPU or another thing on the cartridge (read: costs money). The configuration file is around 800-900Kbytes, which if the NES CPU loaded would take a Long Time(tm). At least 5-10 seconds or more.

It'd be possible to build a microcontroller on the board to do some of the work but this would cost money. I wanted to keep the costs of the cartridge down to make it more affordable. Adding a micro would make it better but add to the cost. I have not totally given up on a micro but I have to check out how much it'd cost. It'd also slow the SD card stuff down a little but I think it might be acceptable speed wise. 2-3 seconds to load a typical MMC3 game like SMB, probably.

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PostPosted: Thu Jul 30, 2015 5:06 am 
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Didn't think microcontrollers costed that much but I guess you need an expensive one. I'd prefer to keep down the cost though since the price is already quite steep compared to the Everdrive, and especially if we are counting shipping from USA.

So any plans for a 60-pin version for us Famicom/Famiclone users?


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PostPosted: Thu Jul 30, 2015 5:54 am 
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tokumaru wrote:
Classic Game Boy is cool and all, but the Super Game Boy already takes care of that.

I imagine that buying this with the Game Link connector option would be cheaper than buying an EverDrive GB, a Super Game Boy 2 (only the rare SGB 2 has Game Link), and an EverDrive N8.


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PostPosted: Thu Jul 30, 2015 9:13 am 
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I'd be interested in this, even with just Classic GB support.

The color reduction experiments are interesting, but I would be unlikely to use them for much.


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PostPosted: Fri Jul 31, 2015 12:31 pm 
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kevtris wrote:
I might give it a try on the systems I have to see what it'd look like.

Please do share the results!

Quote:
I did try benham colour once and it was... interesting.

Sounds kinda crazy... and not practical at all!

Quote:
I was expecting a single configuration.

I see... that's not what I was expecting, considering how most flash carts work. Would it really be possible to fit everything you originally wanted, at the same time? Lots of mappers (including full MMC5) + GB(C) + FDS + NSF Player... sounds like a lot!

Anyway, please keep us updated on the design decisions, and how they could affect the final price.


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PostPosted: Sat Aug 01, 2015 5:04 am 
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tepples wrote:
I imagine that buying this with the Game Link connector option would be cheaper than buying an EverDrive GB, a Super Game Boy 2 (only the rare SGB 2 has Game Link), and an EverDrive N8.


Some of us are already set ;)

I don't think I would play GB ROMs on an NES much, but it would be a good excuse to use up a little extra wasted space on these huge 1gig+ SD cards.

A new flash cart would be nice though, especially if it supported all of the mappers that EDN8 doesn't. Proper FDS expansion audio would be great too, though it has yet to be confirmed.


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PostPosted: Sat Aug 08, 2015 6:33 pm 
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I'd definitely buy one! Especially if it were easy to update.


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PostPosted: Sat Aug 15, 2015 8:47 am 
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been sitting on the fence about which cart to get for a while now, but I'd wait for this.


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PostPosted: Mon Aug 17, 2015 5:13 am 
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If GameBoy is included it would be neat to support the MegaDuck clone as well since it does use a GBZ80 as well. I believe the only difference between MegaDuck and GameBoy games is memory mapping.


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PostPosted: Mon Aug 17, 2015 2:01 pm 
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I would be very interested in it even if it is just for running Little Sound DJ on another device than the Super Game Boy. For that reason emulating plenty of SRAM is important too.

I am assuming the refresh rate of the Game Boy would be locked to the updating of the CHR data the NES is displaying so there isn't tearing / lag.


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