Search found 17 matches

by GreenLine
Mon Jun 06, 2011 8:09 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 421560

HardWareMan wrote:I got an opportunity to make decap of YM2612. Should I? It will cost, but I think I can handle it.
PS Hi-res photos ofcourse will be shared. :3
I think it contains the same tables as the "OPLx decapsulated" document, but if you decide to do the decap I'd like to contribute to the cost.
by GreenLine
Mon May 30, 2011 2:23 pm
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 4015

I have read the thread, several times actually... it's legendary! :-) Since reading that thread, I've been trying to understand the reasons behind the important design choices done with the YM2612 and similar chips. That's basically what keeps me interested in emulation. Mind you, I'm still happy wh...
by GreenLine
Mon May 30, 2011 10:20 am
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 4015

I've modified MAME to use the formula:
att -= template_step + (att >> 4)
It works at a first glance but will take me some time to do better tests.
by GreenLine
Sun May 29, 2011 12:50 am
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 4015

GManiac wrote:EG uses next formula for ATTACK RATE = 1
att += not(att) asr 4
Amazingly, the formula derived by the patent provides the same values for attack rate = 1:
att -= 1 + (att >> 4);

However, they produce different sequences when attack rate > 1.
by GreenLine
Sat May 28, 2011 10:40 pm
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 4015

Thanks a lot for this data, it's very precious to me as I have no way (and not enough knowledge) to collect it with such precision! It will now take me a while to digest it and see how it fits with the formula described in the patent. :) Your explanation was very clear. If by any chance you have col...
by GreenLine
Fri May 27, 2011 10:24 pm
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 4015

YM2612 shape of envelope attack

Maybe this is already well understood but it's all new to me so I though it doesn't hurt to share. After quite a bit of research, I've found this interesting patent: http://www.google.com/patents?id=2S4pAAAAEBAJ&printsec=frontcover&dq=4928569&hl=en&ei=iCHgTY73D8_rsgbgwKHBBQ&sa=X&oi=book_result&ct=re...
by GreenLine
Thu May 26, 2011 8:59 pm
Forum: Megadrive/Genesis
Topic: Megadrive Maps
Replies: 3
Views: 1987

DOS character mode is a very good example. By redefining some characters (=tiles) it was possible to obtain interesting results even in text mode: http://www.ascotti.org/programming/graphics/tgx_demo.gif BTW a quick explanation of the tile system for Pacman can be found here: http://aarongiles.com/m...
by GreenLine
Tue May 24, 2011 7:43 am
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

EU ones don't have that switch on them, its an USA only thing. I wouldn't really say those "HDG-SS" variations are rare in EU, they seem easier to find than non HDG models. True, I'm from Italy and now that I know what to look for, it seems that most MD1 on eBay have the HDG-SS signature. But I got...
by GreenLine
Mon May 23, 2011 5:44 pm
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

TmEE co.(TM) wrote:Yes, its got YM2612 in it.
Great, thank you! :-)
by GreenLine
Mon May 23, 2011 5:20 pm
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

Here's a picture of the console:
Image
And if it can be useful the back (with a strange switch that I don't know what it is):
Image
Is the version with the YM2612?
by GreenLine
Mon May 23, 2011 11:49 am
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

TmEE co.(TM) wrote:The ASIC has YM3438 in it, which fixes quite a few bugs of YM2612, which results in cleaner sound... now if analog sides of those later models wren't so crap...
Ah... there is hope, thanks for the info! :D
by GreenLine
Mon May 23, 2011 11:44 am
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

Check the mother revision. I mean, are you sure that the Genesis that you bought does not have the VA7 revision of the motherboard?, because there's no YM2612 inside of that mother, only a nasty ASIC based sound generator. Ohi Delek... you just sent a shiver down my spine! :shock: I don't know what...
by GreenLine
Sun May 22, 2011 8:09 pm
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

Well... first things first! :-) Yesterday I bought a Sega Genesis and today I spent quite a bit of time playing Golden Axe and other titles... what a wonderful system it is! There is no way I'm going to open and destroy that thing, so now I'll have to find another copy or some other way to get my ha...
by GreenLine
Tue May 17, 2011 7:44 am
Forum: Sound
Topic: Okay... how DO you make OPN voices?
Replies: 4
Views: 2364

With respect to FM sounds I found this information very useful: http://noisesculpture.com/synthesizer-boot-camp There are several videos that show the process of forming sounds with lots of examples. The author also publishes a free e-book with good info: http://noisesculpture.com/how-to-make-a-nois...
by GreenLine
Mon May 16, 2011 9:16 pm
Forum: Sound
Topic: Best way for testing a YM2612 emulator?
Replies: 21
Views: 8045

I like the Teensy! What holds me back is having the thing shipped all the way to Italy, not much for the extra cost but rather for having to wait for weeks and then risking that the package never arrives (shipping by courier is about $70, too much for me). The Arduino Uno (http://arduino.cc/en/Main/...