nesdev.org

Let us know how it goes. There is a lot of stuff that is 3V. I wonder if the PPU would be the same? I did a pseudo-scientific test today. It seems to be working! I made up two versions of the same circuit. One used several logic gates and flip flops, and the other used a CPLD with the same parts co...

Thank you, that cleared up my confusion.

From what I've read, the PAL NES runs on a different clock speed than the NTSC counterpart and ends up executing instructions a little bit slower. I have two questions: 1) What is the external clock speed into the 2A07? 2) If #1 is less than 21.47727 MHz, why is there a whole different processor? I'...

Wasn't part of the issue with the PowerPAK and the FPGA needed being expensive cause it was an older 5V type? Or am I mistaken? I'm looking at using some CPLDs that have 3.3V outputs and 5V tolerant inputs. As long as the 2A03 can see 3.3V as logic high then there is no problem with communication. ...

That sounds promising. I'll give it a test soon and see what magic happens.

Has anyone ever seen a 2A03 datasheet? I'd love to have one even in Japanese.

HMOS is an improved version of NMOS, isn't it? I noticed the HMOS SID chips that I have are rated for 2V being logic high with a 5V power supply. How different is NMOS?

The first thing that I have to ask is what qualities you hear in the samples that you like. The samples I've heard in games tend to be all over the place in terms of quality. Sometimes they're layered with noise to fake better high frequencies (like the sweeeet snare drum in the first track of Ninja...

I wish it was MATLAB, but I can't afford the $3000+ price tag. Instead I use GNU Octave. It's similar in theory and tries to be compatible with MATLAB scripts. It is far more fussy and missing a lot of features, but it is also free. For putting together stuff like this it's great.

I put together this blog post that may be helpful to some in understanding 1-bit DPCM. When I was learning about it originally I had some problems finding illustrations of what was going on.

Here it is.

I keep running into these really simple clarifications that I don't find answers for anywhere else. Someone here always seems to know what's up. I'm trying to get a better handle on programming a 2A03 from scratch. I like to understand everything completely before I start changing things. From what ...

I was hoping it would be CMOS/TTL compatible. It would save some parts/hassle

I haven't had any problems driving the 2A03 with 5V CMOS, but that's the most ideal possible case.

Looks like it'll have to be open-drain or buffered circuitry.

Bregalad wrote:NMOS technology (which is fully compatible with CMOS I guess)

Is 3.3V logic enough to drive it?

This is a pretty simple question. What is the threshold voltage for what the 2A03 sees as a logic high coming in?

but the sound engine has that nasty retrigger any time the upper 4 frequency bits update. I'm not familiar with this side effect( not vibrato, I know what that is). You get some sort of unwanted sound artifact when updating the period system at a higher rate or something? Oops, I meant upper 3 freq...

How do most games go about getting vibrato on the square wave channels? Is it alternating up/down sweeps? Originally I was just planning to modulate the pitch manually, but the sound engine has that nasty retrigger any time the upper 4 frequency bits update. I was thinking careful programming of the...