Posted: 7/3/2016 8:34 PM
Post subject: FCEUX Mod Request - CPU Overclocking
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Gamester
Joined: 7/3/2016
Posts: 4
Hey guys, New here :-) Ok, so first off, I love FCEUX and it has been my favorite NES emulator for a long time. However, there is one thing missing from this emulator, as well as any other NES emulator, that is preventing me from achieving total NES emulation bliss. I used to do quite a bit of NES console modding in the past and my favorite thing to do was overclock the CPU to remove lag/slow down in later games like TMNT3 and Kirby's Adventure. I found that setting the CPU frequency to 2.5MHz was a good speed to fix lag in most games without breaking them and it really smoothed out gameplay. I have been on the search for a long time for an emulator that would allow for CPU frequency adjustment, but unfortunately have never found one to date. So, since FCEUX is open source; could someone possibly make a modded version of the current release that either has the CPU set statically to 2.5MHz or has adjustable frequency? I don't think this kind of change would be too difficult to do for an experienced coder, but it is has been more than 10 years since I have coded anything in C language and I no longer have the tools or knowledge to accomplish this myself. If anyone could do this for me it would be highly appreciated and would make me and others with this wish extremely happy campers! Thank you, Gamester
Posted: 7/3/2016 8:42 PM
Post subject: Re: FCEUX Mod Request - CPU Overclocking
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Bisqwit
Editor, Active player (296)
Joined: 3/8/2004
Posts: 7469
Location: Arzareth
Considering the CPU clock works by dividing the PPU clock, and the PPU clock is intimately tied to how composite video works, how did you do it? I am assuming you are talking about hardware mods.
Posted: 7/3/2016 8:56 PM
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Gamester
Joined: 7/3/2016
Posts: 4
Yea, it was a hardware mod with a frequency change to the CPU via adding an oscillator... http://www.thejobbitt.com/nes-guides/nintendo-nes-001-overclocking-guide/ Of course some games that were very dependent on CPU/PPU frequency, like Battletoads for example, would break; but most games would work just fine at 2.5MHz and the only side effect was higher pitch volume... https://www.youtube.com/watch?v=lHPXUosOeRc
Posted: 7/4/2016 6:37 AM
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Spikestuff
They/Them
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Flash TASer of 2022 PSX TASer of 2016
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Posted: 7/4/2016 3:09 PM
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feos
Site Admin, Skilled player (1236)
Joined: 4/17/2010
Posts: 11264
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NES TAS of 2011
https://sourceforge.net/p/fceultra/code/3230/log/ tl;dr: overclocking has been in fceux svn for a year, and now, after fixing it for a few games, we'll be releasing a new version soon. The principle is way easier and more reliable than speeding up the cpu: we just add extra scanlines to ppu loop and vblank, that's how dendy works. But while on hardware such scanlines slow down gameplay, emulators aren't tied to internal cpu speed, we run it at whatever speed we please. So if still running at 60 fps, we get overclocking with additional scanlines. In games where postrender scanlines make them buggy (contra force), use vblank scanlines. Config -> Timing. http://rgho.st/6LRDDYYTz
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Posted: 7/5/2016 3:43 AM
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Gamester
Joined: 7/3/2016
Posts: 4
Amazing, this is perfect! Thanks a million as you guys have made me one happy guy :-D I didn't even know that there was an actively updated version of FCEUX out there like that. That scanline mod is brilliant and works fabulously! I never thought I would ever see such a smooth NES emulation experience, but this is superb! I look forward to future releases too and will keep an eye on the progress. Thanks again! -Gamester