nesdev.org

If I wanted to link the diagram from the wiki, would it be best to just link directly to the forum, or is there some possibly more permanent place I could put it? (Don't have any 24/7 servers myself. :/)

I'm updating the wiki to add some missing information and clarify some stuff that confused me the first time I was reading it. I'm currently looking at the http://wiki.nesdev.com/w/index.php/Standard_controller page and the way the controller strobe works in particular. Does the following sound righ...

Another simple way to handle mirroring that's admittedly a bit less "physical" than beannaich's variant (no explicit address decoding) is to split PRG and CHR into a bunch of segments corresponding to the finest granularity any of the mappers can switch out and then do mirroring/bank switc...

Here's an updated version that points out that the last tile fetch is unused and adds a note about fine x. The part about the shift registers is wrong. Fine X indexes into the upper 8-bits, inversely (15-fine x). They shift left, every 8 dots the lower 8-bits are reloaded with the fetched data. :P ...

Here's an updated version that points out that the last tile fetch is unused and adds a note about fine x.

Edit: upper<->lower. I keep thinking right->upper for some reason.

http://www.obelisk.demon.co.uk/6502/reference.html is a good basic reference for instruction timing. You might be misled if you read something like http://nesdev.com/6502_cpu.txt (notice the "Notes:" section though), because the fetch of the next opcode is included among the steps and won'...

Zelda 2 has a similar problem with left+right. The starting area where you are inside the palace where Zelda is asleep, if you press left and right at the same time you can actually outrun the game itself and see the name tables and attribute tables being updated. http://www.youtube.com/watch?v=Ka_...

Talked to Quietust and did some more tracing in visual 2c02, and it looks like the secondary OAM clear and sprite evaluation is skipped on the pre-render line. Updating the diagram to reflect this. This might also mean that it's possible for sprites to affect the rendering of the first scanline some...

WedNESday wrote:

Bisqwit wrote:That is a very nice diagram.

Biggest understatement since nesdev's conception.

Glad you like it. I'm thinking about doing another one with all the cpu/ppu/ciram/cart address/data bus connections, since I'm still a bit hazy on some of the details of that.

Bisqwit wrote:That is a very nice diagram.

Thanks.

Midframe state changes and PPU register access is tricky - especially if you want to produce exactly the same glitching as on the original hardware. For that you have to consider when different data is loaded by the PPU, etc., and I'm not even sure the exact timing that goes into e.g. enabling and d...

In case it hasn't been mentioned, changing the vscroll (which requires setting loopy_v), switching banks, or doing other stuff that affects rendering "immediately" probably can't be done without glitching during the last 20 ticks or so of hblank, as the first two tiles for the next scanlin...

If the diagram looks correct now, perhaps it could be linked from relevant parts of the wiki. I could update the out-of-date pages while I'm at it.

Pressing up and down simultaneously in the vertical tunnel level is an insta-kill in Battletoads.

I have a weird bug in that level where both the birds and the player sometimes become invincible. I wonder if that could be a left-right thing as well.

Rid wrote:Hi ulfalizer,

I would like to thank you for your work on this diagram (and everybody who helped you of course)!
It will be very useful for people like me who don't speak english.

No problem. Your English seems fine though.