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PostPosted: Thu Nov 05, 2015 5:24 am 
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I'm currently implementing MMC3's scanline counter and I just have a question to clarify.

If I have both sprite and BG patterns set to $0000 (meaning no transition of A12 from low to high), does the scanline counter get clocked every 2 scanlines due to increment of PPU's Fine Y on PPU clock 256? (I say every 2 scanlines because it flips between odd and even fine Y values)


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PostPosted: Thu Nov 05, 2015 5:31 am 
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Joined: Sun Sep 19, 2004 10:59 pm
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breathermachine wrote:
I'm currently implementing MMC3's scanline counter and I just have a question to clarify.

If I have both sprite and BG patterns set to $0000 (meaning no transition of A12 from low to high), does the scanline counter get clocked every 2 scanlines due to increment of PPU's Fine Y on PPU clock 256? (I say every 2 scanlines because it flips between odd and even fine Y values)


No, because that fine Y bit does not appear on the address bus at A12 - it only affects A0, and even then only during pattern table fetches.

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