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PostPosted: Mon Feb 06, 2012 10:26 pm 
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tepples wrote:
bunnyboy wrote:
Other than verifying how it syncs with the PPU I don't see what decapping would gain.

Yes, verifying how it syncs with the PPU, so that we can 1. make a clone that syncs the same way, and 2. predict what effect VRAM writes during vblank would have.


Would that information be discernible from the decapsulation process described here: http://soltecelectronics.com/products_quality_electronic_parts.html? (about one screen down)


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PostPosted: Mon Feb 06, 2012 10:52 pm 
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tepples wrote:
bunnyboy wrote:
Other than verifying how it syncs with the PPU I don't see what decapping would gain.

Yes, verifying how it syncs with the PPU, so that we can 1. make a clone that syncs the same way, and 2. predict what effect VRAM writes during vblank would have.


Why is it seen as so impossible to redesign this logic ourselves???


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PostPosted: Tue Feb 07, 2012 7:53 am 
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MottZilla wrote:
Any details on what is and isn't implemented? I don't think until now there has been any working MMC5 support. I tried Castlevania 3 and it started up ok and looked alright through the first level. But I forget if later on it uses features that might not be implemented or not.

Vertical-split scrolling and sound are disabled in this one. Everything else SHOULD work, but there are bugs here and there that I haven't tracked down yet. Occasional gfx corruption on some Koei games, for example (EXRAM gets trashed somehow). The special MMC5 stuff (extended nametable, extended attribute, fill mode, split BG/sprite CHR banking) and IRQs work fine as far as I know.


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PostPosted: Tue Feb 07, 2012 11:49 am 
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Excellent. Thanks Loopy. Even if it is incomplete it's better than the absolutely nothing that we had before. Thanks again for all the other mappers you've contributed too.


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PostPosted: Tue Feb 07, 2012 5:22 pm 
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Yes, thanks Loopy! This is not bad for a beta mapper!


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PostPosted: Tue Feb 07, 2012 5:39 pm 
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infiniteneslives wrote:
Why is it seen as so impossible to redesign this logic ourselves???


It isn't seen as impossible, just hard/expensive with no big benefit. And redesigning it doesn't need an exact copy so the knowledge already contained in emulators is almost certainly enough. Decap would just get the precise logic, which could probably be figured out with other tools like logic analyzer instead.

Kevtris' console shows its not impossible, but he did cheat with hooks into the NES PPU :)


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PostPosted: Tue Feb 07, 2012 5:42 pm 
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loopy wrote:
MottZilla wrote:
Any details on what is and isn't implemented? I don't think until now there has been any working MMC5 support. I tried Castlevania 3 and it started up ok and looked alright through the first level. But I forget if later on it uses features that might not be implemented or not.

Vertical-split scrolling and sound are disabled in this one. Everything else SHOULD work, but there are bugs here and there that I haven't tracked down yet. Occasional gfx corruption on some Koei games, for example (EXRAM gets trashed somehow). The special MMC5 stuff (extended nametable, extended attribute, fill mode, split BG/sprite CHR banking) and IRQs work fine as far as I know.


Thank you, keep up the great work.


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PostPosted: Wed Feb 08, 2012 3:15 am 
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bunnyboy wrote:
infiniteneslives wrote:
Why is it seen as so impossible to redesign this logic ourselves???


It isn't seen as impossible, just hard/expensive with no big benefit. And redesigning it doesn't need an exact copy so the knowledge already contained in emulators is almost certainly enough. Decap would just get the precise logic, which could probably be figured out with other tools like logic analyzer instead.


Yeah that was kinda what I was thinking. I guess the point I was trying to make was cracking the secrets of the MMC5 isn't the only option for us to gain these features. That's what most people seem to believe. It's simpler, cheaper, and less uncertainty for us to just re-design logic to provide similar features to what the MMC5 has. There's no point to crack it open, just design something for ourselves... Especially if you're looking to create a game that you'd like to produce.


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