Search found 429 matches

by James
Wed Sep 10, 2014 10:21 am
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5438

Re: Audio and Video Sync

Around .01-.05% in my implementation.
by James
Wed Sep 10, 2014 8:34 am
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5438

Re: Audio and Video Sync

Anes wrote:what is the best way to sync audio and video??
Sync to vblank (assuming 60Hz) and continually resample your audio to that (variable) rate.
by James
Fri Aug 22, 2014 7:27 am
Forum: NESemdev
Topic: stereo sound effect?
Replies: 14
Views: 4251

Re: stereo sound effect?

Try playing your mono output through one channel (L/R) and a slightly delayed copy through the other.
by James
Thu Aug 07, 2014 8:30 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

I tested this in Visual 2C02...while rendering the bus is controlled by the rendering logic, and therefore not directly affected by the change to loopy_v) Nice job digging into this! It may (or may not) be worth noting that Safari in Letterland uses an MC-ACC, which James has shown has similar but ...
by James
Tue Aug 05, 2014 9:46 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

You should use the following logic: clock the IRQ counter when A12 transitions from low to high after being low for a sufficient period of time (I use 5 CPU cycles). This will generally happen at PPU cycle 260, but it's easier to deal with the edge cases by simplifying the conditions for clocking th...
by James
Sun Aug 03, 2014 1:03 pm
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

You're going to have to get your hands dirty. Run it in a debugger and break on any PPU accesses >= 0x3000 then trace it out from there.
by James
Sat Jul 26, 2014 11:13 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

MMC3 IRQ counter should not be clocked by accesses >$2FFF. Filter those in your mapper or ppu code and burai fighter should work correctly.
by James
Sat Jul 26, 2014 8:07 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

This is not the right way to fix it. You will break other games.
by James
Tue Jul 15, 2014 8:26 am
Forum: NESemdev
Topic: MMC5 audio polarity
Replies: 9
Views: 2731

Re: MMC5 audio polarity

ok -- I think I get it now. What you're saying is that, pre-highpass filter, whether the signal looks like this: 2A03 ---- | | | | 0v -------------------- | | | | ---- MMC5 or this: 2A03 ---- | | | | -- -- ---- | | | | ---- MMC5 0v -------------------- the output post-highpass is the same. Right?
by James
Tue Jul 15, 2014 7:30 am
Forum: NESemdev
Topic: MMC5 audio polarity
Replies: 9
Views: 2731

Re: MMC5 audio polarity

This seems to work fine, but I have a couple of (maybe dumb) questions: - Where is the MMC5's negative voltage source? - Why doesn't this cause issues? For example, wouldn't similarly setup square waves on the APU and MMC5 cancel each other out? try subtracting the MMC5's output from 30. That's inve...
by James
Mon Jul 14, 2014 11:05 am
Forum: NESemdev
Topic: MMC5 audio polarity
Replies: 9
Views: 2731

Re: MMC5 audio polarity

Signed signals aren't a problem; I'll give it a try. Thanks, guys.
by James
Mon Jul 14, 2014 10:26 am
Forum: NESemdev
Topic: MMC5 audio polarity
Replies: 9
Views: 2731

Re: MMC5 audio polarity

So the MMC5 is actually outputting a negative voltage?
by James
Mon Jul 14, 2014 10:10 am
Forum: NESemdev
Topic: MMC5 audio polarity
Replies: 9
Views: 2731

MMC5 audio polarity

The MMC5 audio page on the wiki states that "the polarity of all MMC5 channels is reversed compared to the APU." What does that mean, exactly? Should the 0s and 1s in the APU's duty cycle sequences be swapped? Duty Waveform sequence 0 0 1 0 0 0 0 0 0 (12.5%) 1 0 1 1 0 0 0 0 0 (25%) 2 0 1 1 1 1 0 0 0...
by James
Mon Jun 30, 2014 11:04 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

*Spitfire_NES* wrote:is this something i need to check for on nestopia's end for james? Trying to figure out anything i can to have accurate emulation. :beer:
I don't know. You should probably hold off until there is a definitive answer to how this works (which will likely involve tests on real hardware).
by James
Mon Jun 30, 2014 9:24 am
Forum: NESemdev
Topic: Nestopia and Ninja Gaiden/Burai Fighter
Replies: 107
Views: 23705

Re: Nestopia and Ninja Gaiden/Burai Fighter

Was just thinking about this a bit more. I've only implemented this fix on $2006/$2007 access, not on normal accesses during rendering. So maybe this behavior only applies then...

edit: It must only apply then. The PPU doesn't access $3xxx during rendering (see Brad Taylor's 2C02 reference).