nesdev.com
http://forums.nesdev.com/

PAL NES, sprite evaluation and $2004 reads/writes
http://forums.nesdev.com/viewtopic.php?f=3&t=15763
Page 2 of 2

Author:  thefox [ Mon Apr 17, 2017 12:19 am ]
Post subject:  Re: PAL NES, sprite evaluation and $2004 reads/writes

I adapted a new notation below, hopefully it's self explanatory. Basically, 24-, * = "24 -, rest *".

PalRendOff1_v3.nes
- 24-, *
- I'm quite sure I got a 24-, 46*, - pattern when the first few times I tried this, but after the 24-, * first appeared it always appeared, over MANY tries (powerons/resets). (I may have been running a wrong test by accident the first few times, who knows.)

PalRendOff2_v3.nes
- 80-, *
- Not really consistent with results from PalRendOff1_v3.

PalRendOn1_v3.nes
- This worked as expected: 24-, *

PalRendOn2_v3.nes
- *
- Certainly not expected, looks like something goes wrong while it tries to read during VBL.

Good news is that the results were consistent across resets/powerons (discounting the first test, but that could've been my mistake). Unfortunately they don't line up with previous results.

Author:  Sour [ Mon Apr 17, 2017 3:46 pm ]
Post subject:  Re: PAL NES, sprite evaluation and $2004 reads/writes

Well, that's... confusing. I'm not really quite sure what to make of those results.

blargg's framework is able to print the values of registers on the screen, so I'll try to come up with a slightly different test that displays the values actually read from OAM - maybe it'll help figure out what's actually going on.

Page 2 of 2 All times are UTC - 7 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/