Search found 206 matches

by Snake
Mon Mar 22, 2021 4:37 am
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 117
Views: 7567475

Re: Questions on writing a new Mega CD emulator

For years, the software to drive this C-Trac CD emulation hardware was missing from the public domain. It surfaced more recently Is that the virus infected SEGA.EXE that was floating around a while back? If so, and nobody has done it already, I fixed that and was going to post it here - then got di...
by Snake
Mon Mar 22, 2021 3:56 am
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 117
Views: 7567475

Re: Questions on writing a new Mega CD emulator

It was Steve Snake Nah, I believe he's talking about Mr. Quinn, of AGES. I forget his first name :-( He got all this stuff working well before any of us. he probably has some "internal" information I had no more info than anybody else did at the time. I had to go out and buy a SegaCD and burn about...
by Snake
Mon Mar 22, 2021 2:36 am
Forum: Demos
Topic: Direct Color Demo using DMA
Replies: 91
Views: 115221

Re:

Actually i don't know who originally had the idea but it is really neat, kudos to him for having the idea... I believe that would be me, sometime between 2004-2006. I sent a little demo showing a couple of pictures of Zooey Deschanel to TmEE sometime in 2010. But the image in that demo wasn't stabl...
by Snake
Sat May 24, 2014 7:32 am
Forum: Mega/SegaCD
Topic: Reading subcode data on the MegaCD
Replies: 12
Views: 30015

Nemesis wants to do this to rip Mega Laserdiscs - what burners can and cannot burn do not matter here. Well, it's also easy to generate the data that's actually readable (i.e. the L2 error correction stuff, and the PQ (i think?) subcodes) in software. The rest doesn't matter because it can't be rea...
by Snake
Wed May 21, 2014 5:30 am
Forum: Mega/SegaCD
Topic: Reading subcode data on the MegaCD
Replies: 12
Views: 30015

Thinking about this a little more... Maybe you need to use the ROMREAD stuff to get the audio. (*edit* or just play it as audio and call CDCREADP as TascoDLX said above...) At a hardware level, there is only one way to read the disc - the PLAY command. Maybe the only difference in the BIOS calls is ...
by Snake
Wed May 21, 2014 5:11 am
Forum: Mega/SegaCD
Topic: Reading subcode data on the MegaCD
Replies: 12
Views: 30015

I've been out of the loop forever and this is all from memory but hopefully it's useful... Do any games actually use these functions? No. these functions only return 32 bytes between them It's because of the odd way this stuff is interleaved. So, to get it all, you'd have to call either one when dat...
by Snake
Thu Apr 08, 2010 10:34 am
Forum: Video Display Processor
Topic: How does Sonic2 handle sprites for interlace mode?
Replies: 7
Views: 9261

Correct. Well, sort of. In interlace mode the system is still only displaying 224 lines per frame, it's just that one frame is all the odd lines, and the next all the even lines. So, you still only need 224 entries in the scroll table. You could change the scroll table every frame, and have all 448 ...
by Snake
Mon Jan 25, 2010 3:31 am
Forum: Megadrive/Genesis
Topic: What kind of IA can use a 16bit game?
Replies: 9
Views: 10800

Well, the Genesis should be able to handle a LOT more than this. You must be doing something pretty complicated to have issues with only 40 helicopters. Can you elaborate? I don't think it's true that all games use precalculated paths. Some do, for sure, and some use a mixture. But generally a lot o...
by Snake
Mon Jan 18, 2010 5:21 am
Forum: Video Display Processor
Topic: Megadrive video timings
Replies: 123
Views: 156712

This is straight from the Nomad screen? It may not have enough colour resolution. Do those things have a TV Out?
by Snake
Mon Jan 18, 2010 1:19 am
Forum: Blabla
Topic: some spare parts laying around.. so I built a flash cart
Replies: 11
Views: 11906

What was the cart before you 'converted' it?
by Snake
Sun Jan 17, 2010 6:16 pm
Forum: Video Display Processor
Topic: Megadrive video timings
Replies: 123
Views: 156712

Not a big deal, but it's nice to know. Oh, sure, very nice :) But a bit different to what people have been implying to me for a long time, i.e. that the whole thing was way off. It would be nice to know if steps by 36 are pretty damn close, so I can keep using those :D From what I can tell the step...
by Snake
Sat Jan 16, 2010 11:42 pm
Forum: Super 32X
Topic: DMA to PWM
Replies: 43
Views: 45877

mic_ wrote:Is there a version of Kega where this works ok? It's all distorted in 3.51, which makes it impossible to dev because you never know if there distortions come from a bug in your program or from the emulator.
It works perfectly in Mono, only Stereo is distorted. I'll fix it up when I get a chance.
by Snake
Fri Jan 15, 2010 1:14 am
Forum: Super 32X
Topic: DMA to PWM
Replies: 43
Views: 45877

One thing I was wondering - is it really necessary to bang on the FRT like in all the SEGA examples? No. That's probably down to the workaround they provided for a hardware bug. Basically when you hit the reset button not everything gets reset, and this can cause the whole system to lock up. The wo...
by Snake
Thu Jan 14, 2010 5:47 am
Forum: Super 32X
Topic: DMA to PWM
Replies: 43
Views: 45877

Chilly Willy wrote:Yeah - looking at the diagnostic cart
....and I don't even know where that came from - it certainly was not supplied with any of my many dev kits. I'm not even sure it was supposed to leave Sega.
by Snake
Thu Jan 14, 2010 12:51 am
Forum: Hardware
Topic: MD2 + YM2413 = Total Awesomness :D
Replies: 14
Views: 18914

This is SERIOUSLY awesome. I want one.