Is the genesis really that hard to emulate?

katraqueyous · Post by **katraqueyous** » Thu Feb 21, 2002 5:12 pm

I recall someone saying that the genesis is harder to emulate than the Snes. Is that true, and how?

kRYPT_ · Post by **kRYPT_** » Thu Feb 21, 2002 7:10 pm

Don't quite me on this one, but I believe it had to do with multiple CPUs inside the Genesis.

katraqueyous wrote: I recall someone saying that the genesis is harder to emulate than the Snes. Is that true, and how?

snake78 · Post by **snake78** » Thu Feb 21, 2002 7:16 pm

I believe that's the reason why the Sega CD is so hard to emulate (since it had its own cpu that was perfectly timed with the Genny's).

Genesis Technical Specs

Model Number:
MK-1601 (r1), MK-1631 (r2), MK-1641 (r3)

CPU:
Motorola 68000 at 7.61 MHz

ROM:
1 MByte (8 Mbit)

RAM:
64 KByte

Co-processor:
Z80 @ 4 MHz (Not Present in MK-1631)
controls PSG (Programmable Sound Generator) & FM Chips

Sound RAM:
8 KBytes

Colors Available:
512

Colors on screen:
64

Pixel Resolution:
320 x 224

Graphics:
VDP (Video Display Processor) dedicated video display processor,
controls playfield & sprites.
3 Planes, 2 scrolling playfields, 1 sprite plane

VRAM:
64 KBytes (Video Ram)

CRAM:
64 x 9-bits (Color RAM)

Sound:
PSG (TI 76489 chip)
FM chip (Yamaha YM 2612)
6-channel stereo
8 KBytes RAM Signal/Noise Ratio: 14dB

System Notes/History

The 3rd in the series, named the Genesis 3, was released by Majesco, not SEGA. Although it was under
permission of SOA, that model is MK-1641, the MK 1601 is the original, and the MK 1631 is the second of the
series.

The Genesis 3 does not have the Z80 processor, and that means the following:
1. Unable to run the MS convertor as it needs the Z80 chip which is the brain of the SMS.
2. Unable to run Game Genie, the Z80 must have played a role in the use of this for code break ins.
3. Unable to run special games such as Sega's Virtua Racing, which again uses the Z80.

The obvious disability of the Genesis 3 is the missing expansion port that used the purpose of running the
SegaCD system. These factors should be taken in consideration if anyone is looking to buy a Genesis system.
-- Contributed by Nestor J. Galeano

Got this info from http://www.vgmuseum.com

miah · Post by **miah** » Thu Feb 21, 2002 7:54 pm

Wow.. Very informative.

drunkensailor · Post by **drunkensailor** » Fri Feb 22, 2002 8:53 am

actually geneisis is just bigger then snes that's why

katraqueyous · Post by **katraqueyous** » Fri Feb 22, 2002 2:48 pm

Is SNES so called 'more powerful' than genesis??

drunkensailor · Post by **drunkensailor** » Fri Feb 22, 2002 3:39 pm

genesis is more powerful then snes

katraqueyous · Post by **katraqueyous** » Fri Feb 22, 2002 4:04 pm

Really? I didnt know that. The snes has more colors on screen right???

atf487 · Post by **atf487** » Fri Feb 22, 2002 5:32 pm

Wow. I always thought a console more powerful came out later. Thats probably the only time that and inferior console came out later.

Heliophobe_ · Post by **Heliophobe_** » Fri Feb 22, 2002 5:59 pm

The SNES had a more powerful graphics chip, but a weaker CPU. For sound chips, it's sort of hard to say, FM and PCM sound are just different, it's sort of a matter of preference.

I sincerely doubt the Genesis 3 doesn't have a Z80 - nearly every Genesis game used the Z80 for sound and music. That's why most games in DCGen don't play with sound - DCGen didn't have z80 emulation in the first release.

sixteen-bit · Post by **sixteen-bit** » Fri Feb 22, 2002 6:00 pm

SNES admittedly has a slower CPU but beats the megadrive in terms of colours displayed on screen and the SNES also has a nifty-cool sound processor, courtesy of Sony I think, which has similar capabilities to a 'tracker module' player on PC (though it does only have 64K of RAM)

SNES also had sprite scaling and rotation which the megadrive lacked.

SmitZo · Post by **SmitZo** » Fri Feb 22, 2002 6:25 pm

The SNES had the better games

apart from maybe the Streets of Rage games

Oz · Post by Oz » Fri Feb 22, 2002 6:28 pm

I'm with Heliophobe, the Genesis 3 most likely had a z80 in it.

Although these sites seem to think it didnt:

http://www.vgmuseum.com/systems/genesis/
http://www.gamedimension.net/gamegurus/genesis/

The Genesis/Megadrive FAQ makes no mention of this:

http://db.gamefaqs.com/console/genesis/ ... enesis.txt

And these sites seem to think it did have a z80:

http://pelikonepeijoonit.net/page.cgi?pkpcode=genesis3
http://www.channel3games.com/platforms/genesis.shtml
http://webmail.nic.fi/~mikkohoo/peijoonit/genesis3.htm

sixteen-bit · Post by **sixteen-bit** » Fri Feb 22, 2002 6:50 pm

I always thought the z80 in the megadrive controlled and co-ordinated the PSG and FM chips, as well as being used for the SMS adapter and other devices.

Anyone have a Gen3 they'd like to open up and see if there's a z80 inside?

katraqueyous · Post by **katraqueyous** » Fri Feb 22, 2002 6:58 pm

Whats a z80? And is this the thing that atani is inputing in the new DCgen?

Heliophobe_ · Post by **Heliophobe_** » Fri Feb 22, 2002 7:08 pm

16-bit Miles wrote: I always thought the z80 in the megadrive controlled and co-ordinated the PSG and FM chips, as well as being used for the SMS adapter and other devices.

Anyone have a Gen3 they'd like to open up and see if there's a z80 inside?

That's exactly what it does (for most games). My guess is that whoever thought the Genesis 3 didn't have a Z80 either A)Noticed that it didn't support the Power Base Converter and incorrectly concluded it was missing the z80 or B) Looked at the circuitboard and couldn't find one (other companies make Z80 clones now and they wouldn't say "Z80" on them).

Katana_ · Post by **Katana_** » Sat Feb 23, 2002 4:50 pm

The SNES is superior to the genesis
Its a lot more advanced able of textured mapping and high colors and music.(which nintendo chose over high speed)

The Genesis was basic, and advanced for its year 1988 in japan i believe
. It had a fairly fast processor which was what sega used to promote its "blast processing"

But as always, its the games that mattered.

Boogerman · Post by **Boogerman** » Sat Feb 23, 2002 4:59 pm

From what I had back in the day, was source code from some orginal Genesis emulators and the trouble they were having was figuring out the video output. It turned out that, although weaker, (technically speaking) the Genesis was harder to emulate because they couldn't get anything drawing. Sound would play, code would be run, controllers read but no visual impact...

While that has nothing to do with DC emulation (It has been figured out now) don't forget that DCGen is quite a recent project compared to DreamSNES and as such is in a more basic state ATM...

Also, completly unrelated, but if you had no idea what was under the hood of the 2 machines and seen Sonic and Mario running side by side (and your not playing) which machine looks more powerful?

DLolos · Post by **DLolos** » Sun Feb 24, 2002 12:14 pm

The genesis is more powerful with its CPU then the SNES. The SNES has a lot more colors then the Genesis. So in a lot of SNES games they needed to include a extra CPU. SuperFX chips and Capcom chips were popular on SNES. Genesis never really needed a extra CPU. Thats why some SNES games like Link would slow down in some cases in the game. Even MegaMan X2 slowed down with the help of the Capcom chip. Genesis was a more speedier system then SNES. SNES has the extra color abilitys not to forget that mode 7 effect you could not get on the Genesis alone. With SegaCD you could but you have a extra CPU I guess to help it out.

Veggita2099 · Post by **Veggita2099** » Sun Feb 24, 2002 12:41 pm

I think the SNES is better then the Genesis. A Good way to compare them is play the Rom of Spider man Xmen vs Arcane. On the SNES version there is better back grounds, more realistic sound effects, and more to it. On Sega Gambits Level music is the same as Wolverenes level music. On SNES there was a clown type music on Wolv's level.

All games that I played on both systems seemed all around better on the SNES then Genesis. And compare the later games made for both systems. While the SNES had games such as Donkey Kong Country 1 2 and 3 Sega has games like Sonic 3D Blast and Vector Man series. The DC series graphics and sound wise blows away any game made on the Sega Genesis, or even the Sega 32X.