nesdev.org

Hi guys,

I was just thinking about a trick I'd like to do with the PPU, and I was wondering if you can mess with $2006 and $2007 when only sprite rendering is enabled. Something tells me it's not possible (have I asked this question before?), but since $2006 and $2007 have nothing to do with the sprites, maybe it is.

Thanks for the help.

Of couse it's not possible, because the PPU needs to acess CHROM or CHRAM to render sprites as well as the palette, using $2006 and $2007 for its own purpose.

You are right. That was just stupid of me to ask that. I wasn't thinking about the sprite patterns, duh!

Doesn't sprite pattern fetching happen during pixels 256-319 of the scanline? If so, then why can't the CPU mess with VRAM during pixels 0-255 if the background is turned off?

I didn't know (or didn't care, before) about this detail, but it looks like something worth trying.

The PPU keeps fetching VRAM for the entire duration of scanline if background or sprites are enabled. The only time it goes completely silent is if everything is disabled.