Search found 203 matches

by Snake
Fri Feb 27, 2009 2:04 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

Ahh, but remember that the attenuation isn't moving past 0x200 during a repeating SSG-EG wave. Ah, this is what I meant, but I didn't explain it very well :) I was assuming the attenuation starts at 0x3FF, and is decremented until it hits 0x200 - at which point it will immediately switch to decay, ...
by Snake
Thu Feb 26, 2009 11:54 pm
Forum: Demos
Topic: Z80 driver - 4 channels player with volume control.
Replies: 15
Views: 6838

now it works, pretty nice, and quality is very good too :D Thanks :D Strangely the quality is better than my first driver which was using similar code at the same output rate :-/ :D I often find I write something better the second time around ;) Probably some bug, typo, or timing error that was too...
by Snake
Thu Feb 26, 2009 11:19 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

The samples are averaging together, which is why you're being left with a regular sine wave at mid-level. I did consider that, but since the sample rate is not divisible by the hardware output rate, I would have expected to see some clear distortion rather than an almost perfect wave - I can see th...
by Snake
Thu Feb 26, 2009 10:41 pm
Forum: Video Display Processor
Topic: HBlank Timings
Replies: 163
Views: 34762

I have another question about DMA Timings. Is it necessary to emulate dma transfert line per line or making all the transfert at start of dma and set the status flag to 0 after necessary cycles is sufficient? For normal ROM to VRAM DMA, the CPU is locked while it happens anyway, so you could get aw...
by Snake
Thu Feb 26, 2009 4:38 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

Care to share? Absolutely, happy to. It's to do with the inverting every cycle thing. I believe my tests were done with AR=0x0A, and one of the inverting patterns. I was looking at what I assume is an inverted attack, and it looks like a perfect sine wave at a constant volume. The samples you provi...
by Snake
Wed Feb 25, 2009 7:52 pm
Forum: Demos
Topic: Tiido's speech synthesizer 3
Replies: 10
Views: 4540

I think you should use phonemes of syllables rather than letters. Then speech will be more clear. A long time ago I did the same thing for russian... :D I've done this type of thing myself. One thing I've always meant to do, but never seem to get around to it, is to attempt to extract samples from ...
by Snake
Wed Feb 25, 2009 6:52 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

Hmm, that is strange. It looks like the one running at the higher frequency has some additional noise on the output signal. I'll take a look. It's probably writing to the DAC at around the same time the chip is trying to read it. I can't say I've done very thorough tests on this. I generally ran on...
by Snake
Tue Feb 24, 2009 11:15 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

What I did is to use the same increment values as when Rate is 0 (infinite rate) Indeed, it makes perfect sense. Can you confirm that output calculation also happen the same way with normal enveloppe ? Meaning that any change to internal attenuation level (for example on Key ON with AR=62,63) If wh...
by Snake
Tue Feb 24, 2009 11:26 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

That's a really good capture of the effect, better than I've seen so far. How did you capture that?
by Snake
Tue Feb 24, 2009 7:51 am
Forum: Demos
Topic: Gameboy on 32X
Replies: 77
Views: 27836

I noticed you are doing some sort of cache purge every scanline. Is this really needed? That's probably going to be slow.

Also, you're doing something with the palette every scanline too. Again, is this needed?
by Snake
Mon Feb 23, 2009 9:00 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

1/ attack rate is set to 62 or 63: you say that the attenuation level is set to 0 but is the next enveloppe update done with Attack or Decay parameters ? Decay. Attack is skipped immediately in this case. 2/ SL is set to 0: does EG enter the susbtain phase once or does it directly jump to release ?...
by Snake
Mon Feb 23, 2009 7:30 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 357476

Wow, huge post :) Kind of odd that you would post this right now. I have a ton of SSG-EG samples I did years ago, but I lost the test ROMs that created them, so I didn't know what I was looking at. This weekend I found them and spent most of it looking into this again. I'll read your post properly l...
by Snake
Fri Feb 20, 2009 12:27 am
Forum: Demos
Topic: Wolf32X - finally in beta!
Replies: 40
Views: 17399

Hmm, well I don't think it matters if you set TH HIGH or LOW first, it just makes more sense to me to do it this way for many reasons. There's no reason at all why you'd need to set it high at the start AND end of the code either. I'm pretty sure the pad will return standard 3-button data for longer...
by Snake
Thu Feb 19, 2009 10:20 pm
Forum: Demos
Topic: Wolf32X - finally in beta!
Replies: 40
Views: 17399

What's REALLY weird is that the six button code doesn't work on Kega Fusion - I'd REALLY like to know why that fails. Gens doesn't do this in a hardware accurate way, just in a way that works with games. Looking at the source you posted in another thread I can tell you how to make this work reliabl...
by Snake
Thu Feb 19, 2009 9:13 pm
Forum: Demos
Topic: Gameboy on 32X
Replies: 77
Views: 27836

Good stuff :) What sort of speed are you getting?