nesdev.org

I'm really close to understanding how this all works now. Two final questions (hopefully). 1. When the attribute shift registers are filled, the attribute byte fetched is fed through a 4 to 1 mux that selects two bits in the attribute byte based on bit 1 of coarse X and coarse Y. The two bits that a...

My 6502 emulator is working correctly :) A few more questions for you guys. I'm having a hard time figuring out how a 8x8 tile is rendered in a scanline. From my understand of how the PPU renders a background pixel from this diagram, it goes something like this: 1. Fetch name table byte 2. Fetch att...

1. How does the PPU know if $2007 wants a read or a write? Does the CPU write a nonzero value for a write and a zero value for a read? What? Where did you get this zero/non-zero idea from? Like 3gengames said, one of the CPU pins indicates whether it's trying to read or write data, and the PPU uses...

Thank you!

One final question for now: How do I emulate the CPU pin for reads and writes on $2007? Do certain opcodes tell the CPU to read to write from that register?

Thank you! Things are starting to make a lot more sense now. Two more quick questions. 1. How does the PPU know if $2007 wants a read or a write? Does the CPU write a nonzero value for a write and a zero value for a read? 2. When a $2007 read occurs, where does the data read go to? Does the PPU just...

Alright guys, bear with me please. I've read through all of the documents on the wiki and read through a ton of threads on here and there are still some things I just do not understand with the PPU. Maybe you guys can clear these things up for me. 1. How often are the PPU registers ($2000-$2007) loo...

I'm writing a NES emulator. I finished the core and passed all of the nestest up until the illegal opcodes came in (I didn't implement those because I assumed they don't matter for commercial games?).

After reading this post I still have a few questions: 1. So I only need to load the pattern tables from CHR-ROM and the rest of the tables will be filled up by the program code (I assume by writing values to $2006?)? I'm still a bit fuzzy on how the attribute and nametables are filled. 2. Where exac...

So should I made a public variable in my cpu class that holds the number of cycles and have it reset once a scanline is done? Or should I be storing the cycles somewhere else? On a side note, does anyone know how to compare my output with the nestest.log output when the two aren't the exact same? My...

I've been working on the CPU emulation for the past few weeks and finally got all of the instructions excuting right. Now I need to go back and add the cycles into the core. Just a few questions: 1. What does cycle counting do exactly? Is supposed to be keeping track of time or are they just arbitar...

Is this it:Ebay

I've been using nesasm to compile a few test codes out and it seems to be working ok. I'm just wondering what programs should I use for compiling, making music, mappers etc.

Thanks for the info, I will start looking into that tongiht.

I've wanted to make nes games for about a year and a half now, about as long as I've known about emulators. I have very limited experience with C coding and Visual Basics.

Where is a good starting point for making games in 6502?