Search found 25 matches

by Mamizou
Mon Feb 04, 2013 4:23 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

Are you using windows if so that is your problem not your computer. When I boot my computer into windows 7 already after it finishes starting up it is using over 1gb of ram but on Debian GNU/Linux on start up it takes about 190mb of ram or less and it never uses that swap on my computer but windows...
by Mamizou
Sat Feb 02, 2013 9:08 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

Also, how are the decapping related things going on ? It has been quite silent around it. I had to wait for a laptop upgrade before continuing to identify the chip parts and whatnot, my machine was swapping itself to death trying to load the massive die image. I started going over it again though, ...
by Mamizou
Wed Dec 19, 2012 7:11 pm
Forum: Megadrive/Genesis
Topic: Mega Drive Wiki Project !!
Replies: 14
Views: 4833

Quick note, due to the amount of spam and such, there's no way to register your own account, so if any of y'all need one, PM me and I'll figure something out. I run a fairly big Mediawiki site, and setting up QuestyCaptcha really helped block out bot registrations. It only works if you have a decen...
by Mamizou
Tue Nov 27, 2012 6:04 pm
Forum: Sound
Topic: YM2612 output buffer
Replies: 11
Views: 4851

The OPN2 actually outputs at 55.5kHz, same as all the other OPN chips. You can see most of the output stage here. The dropping writes is mainly due to limitations on how fast you can actually do things with an OPN2 and the system it's in (see here).
by Mamizou
Wed Aug 22, 2012 9:47 pm
Forum: Sound
Topic: YM2612 CSM Mode - Speech Synthesis
Replies: 6
Views: 4598

One of the sites linked on that Bad Apple video has some CSM programming info for the OPN/OPNA on the PC-8801 here. It also links to a video on NND showing "Sine Wave Synthesis" via MIDI on an 88pro wavetable synth. Pretty amazing. :O
by Mamizou
Fri Jun 01, 2012 5:06 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

This is so cool. I got a noob question.. How do you know which part does what? How does one go about doing this? Mainly by looking at how many bits wide it is. For example, you can see the 10.10 bit wide registers in the PG, the 10 bit registers in the EG, the 14 bit output of the PG leading to the...
by Mamizou
Fri Jun 01, 2012 3:31 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

Here's the chip parts so far . (~500KB) All of the sections in the top-left (not marked with a red box) are the various registers; I haven't yet figured which are which, but I'm going to assume the large and wide part in the middle-left are the main channel registers, and the smaller part in the ve...
by Mamizou
Thu May 31, 2012 6:54 am
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

Just wondering, is anyone else trying to parse through the parts of the chip scan? I've been trying working through them, but my poor computer can't open the full scan without abusing the hard drive. So far I've identified the EG, PG, sine and exponential ROMs, sine/exp. output adder, etc., but actu...
by Mamizou
Wed Apr 25, 2012 10:09 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

If we'd skip the cd block, I'd put my money on the SCU. The DSP part has poor to missing documentation. On the topic of sound chips, the SCSP would be very interesting since it does both FM and PCM (I guess an operator would just read from a PCM buffer instead of the quarter-sine ROM). I think the ...
by Mamizou
Thu Apr 19, 2012 5:07 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 396007

Hi there! I've been monitoring this thread for awhile now and updating the Wikipedia article on the YM2612 as this has progressed. Seeing the OPN2 finally decapped is really amazing, and it's interesting comparing the full die image to those of the decapped OPL2 and OPL3. Seeing a decapped VDP would...