RGB output from composite PPU

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wyatt8740
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Re: RGB output from composite PPU

Post by wyatt8740 »

...This is spectacular. I always thought that since a Commodore VIC can be modded for rgb, a NES should. I must have been right for once! :D
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Quietust
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Re: RGB output from composite PPU

Post by Quietust »

lidnariq wrote:Allow steering of $4014 DMA to $2007 instead of only $2004
Unless you're replacing the entire PPU, I'm not sure that will actually work - last I checked (in visual2c02), the PPU wasn't capable of reacting to such rapid writes to $2007.
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lidnariq
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Re: RGB output from composite PPU

Post by lidnariq »

Oh good point! Visual2C02 indicates that it takes roughly 19 to 22 cycles (5ish pixels?) from the start of io_ce and w2007 until the /WR strobe goes false again, and it seems to be synchronized to various PPU-internal pixel clocks. That's very close to the 6 pixel spacing DMA does, and a PPU program of "W 7 1e / - 0 18 / W 7 18 / - 0 18" does show it getting confused.

If the device controls clocks for the CPU and PPU separately, then it should be possible to work around by slowing down the CPU clock during DMA. I wonder how much is necessary?
tepples
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Re: RGB output from composite PPU

Post by tepples »

Quietust wrote:
lidnariq wrote:Allow steering of $4014 DMA to $2007 instead of only $2004
Unless you're replacing the entire PPU, I'm not sure that will actually work - last I checked (in visual2c02), the PPU wasn't capable of reacting to such rapid writes to $2007.
The PPU wouldn't need to react. The mapper's dual-ported VRAM feature would snoop on $2004 writes, and the program would run DMA transfers to OAM and on-cart VRAM at once, followed by a final DMA to OAM.
hyarion
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Re: RGB output from composite PPU

Post by hyarion »

Looks like someone took the idea and put it in a need little package ready to be ordered.
There are still rooms for improvements though, like configurable palettes, component output etc.
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Drakon
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Re: RGB output from composite PPU

Post by Drakon »

hyarion wrote:Looks like someone took the idea and put it in a need little package ready to be ordered.
There are still rooms for improvements though, like configurable palettes, component output etc.
Personally I'd rather get rgb and use an external rgb to component converter.
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mikejmoffitt
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Re: RGB output from composite PPU

Post by mikejmoffitt »

Ordered one. Hyped. Going to try to cram it into an original Famicom.
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Drakon
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Re: RGB output from composite PPU

Post by Drakon »

mikejmoffitt wrote:Ordered one. Hyped. Going to try to cram it into an original Famicom.
I'd love to see how you'd get it to fit. I can't wait to get my hands on the nes 2 / av famicom adapters.
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mikejmoffitt
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Re: RGB output from composite PPU

Post by mikejmoffitt »

Thought I'd post the URL for anyone else who is interested:

http://etim.net.au/nesrgb/index.htm
zzo38
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Re: RGB output from composite PPU

Post by zzo38 »

Do you have source codes for such device?
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mikejmoffitt
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Re: RGB output from composite PPU

Post by mikejmoffitt »

I imagine he does not want to release such a thing immediately, but given the information provided it shouldn't be too hard to replicate the functionality for someone experienced with PLDs / FPGAs.
zzo38
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Re: RGB output from composite PPU

Post by zzo38 »

mikejmoffitt wrote:I imagine he does not want to release such a thing immediately, but given the information provided it shouldn't be too hard to replicate the functionality for someone experienced with PLDs / FPGAs.
Yes, I expect that can help.
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SkinnyV
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Re: RGB output from composite PPU

Post by SkinnyV »

That's exciting news, but 90$? Seriously?
3gengames
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Re: RGB output from composite PPU

Post by 3gengames »

SkinnyV wrote:That's exciting news, but 90$? Seriously?
When there's nothing else to compete, why make it cheap? Hopefully someone undercuts this stuff. How much does the FPGA cost? rest of the board can't be more than ~$10 assembled.
Pasky
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Re: RGB output from composite PPU

Post by Pasky »

Only thing annoying me is everyone calling the guy a genius when it was thefox's brain child. I ordered one, $90 is somewhat fair, still cheaper than a RGB ppu. Kinda lame there is no component out and his only comment about that was that tvs with component inputs are 'relatively new'...what the hell?
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