Patterntable #1 and FCEUX

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oRBIT2002
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Patterntable #1 and FCEUX

Post by oRBIT2002 » Wed Nov 27, 2013 5:38 am

FCEUX refuses to use patterntable #1 as background for my little .nes (MMC1) experiment and I haven't got a clue why. I clearly specify the correct(I hope) bit in $2000 (bit 4 = 1) but it keeps using patterntable 0. Other emulators (Nestopia, Nintendulator) seems to work properly but not FCEUX (latest build).
Is there a feature I am not aware of?

Thanks in advance

Shiru
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Re: Patterntable #1 and FCEUX

Post by Shiru » Wed Nov 27, 2013 5:42 am

MMC1 can control mirroring with the control register, have you set it up correctly?

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qbradq
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Re: Patterntable #1 and FCEUX

Post by qbradq » Wed Nov 27, 2013 6:02 am

To elaborate a little more, if you haven't initialized all of the MMC1 internal registers, especially those having to do with CHR banking, then you'll have undefined behavior. On the hardware this usually means random behavior. On emulators it means you get their default behavior which may be different between various emulators.

Pop open FCEUX's pattern table viewer and ensure that pattern table #1 contains the patterns you expect it to. If not, you may have this issue. And as always, fully initialize your mapper.

Best of luck!

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oRBIT2002
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Re: Patterntable #1 and FCEUX

Post by oRBIT2002 » Wed Nov 27, 2013 6:48 am

FCEUX pattern/PPU viewer just shows nothing no matter which ROM i try. :( That bug has been there for a few versions..

I'll check out my MMC1 code, I didn't think it had anything to do with which patterntable to use. But I'll check it out..

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Hamtaro126
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Re: Patterntable #1 and FCEUX

Post by Hamtaro126 » Wed Nov 27, 2013 7:17 am

How about adjusting the ''Refresh'' ramp to refresh more instead of less?
AKA SmilyMZX/AtariHacker.

tepples
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Re: Patterntable #1 and FCEUX

Post by tepples » Wed Nov 27, 2013 7:27 am

I still have FCEUX 2.2.0 installed, and its PPU Viewer works. Sometimes you have to close and reopen it to get it to refresh though, especially if you're stepping through with the debugger.

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rainwarrior
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Re: Patterntable #1 and FCEUX

Post by rainwarrior » Wed Nov 27, 2013 7:33 am

Posting the ROM would help us diagnose the problem.

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oRBIT2002
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Re: Patterntable #1 and FCEUX

Post by oRBIT2002 » Wed Nov 27, 2013 7:45 am

Fixing the MMC1 code fixed the problem, thanks.

PPU & Nametable viewer all goes black no matter what setting I've tried in FCEUX. I am not sure why. Anyone else have this problem?

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tokumaru
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Re: Patterntable #1 and FCEUX

Post by tokumaru » Wed Nov 27, 2013 7:56 am

oRBIT2002 wrote:PPU & Nametable viewer all goes black no matter what setting I've tried in FCEUX. I am not sure why.
FCEUX shows the data for specific scanlines. If I'm not mistaken, the default scanline is 0 (you can change this to whatever you want), so it will show whatever is mapped when that scanline is rendered. In games that swap CHR mid-frame, you might have to change this value in order to see the tiles you're looking for. In the pattern table viewer you can also change the palette used to display the tiles, and an all black palette could make all tiles show up black.

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oRBIT2002
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Re: Patterntable #1 and FCEUX

Post by oRBIT2002 » Wed Nov 27, 2013 8:05 am

All black, no matter what settings I change/use. :/

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