nesdev.org

the SNES expansion port?

I'm planning to learn NESasm, SNESasm, and then call a friend of mine who knows a lot about hardware, we plan to do a SNES-CD.

I was thinking about using a Z80 for processor (even some people in the NESDev board said it was confusing to use) and build some devtools that could make Game Making for it as easy as eating pie.

The design tool would be (or will if i can build it) the sort of thing that Game Maker is for PC. Less coding, more gaming.

The extra APU would be the same the Mega Drive uses, the YM2612 (Yes, that's right. I love the meow sound of this chip)

Extra GPU? YM7101.

This might be just a dream, but i would like to know if it is possible...

So, you'll essentially be turning the SNES into a Mega Drive? What's the point really?

Z80 is pretty inefficient, why not make it another 6502 so you don't have to use 2 completely different chips on it? And what needs added on that the SNES can't do by it's self? Also, it works differently from 65 chips, so you may want to see if it's even doable within X ammount of parts.

So, other CPU, other audio, other graphics - completely new system. How this would relate to SNES then?

It doesn't look like the SNES expansion port has an address. I guess you would decode the address on your cartridge, then send the enable signal through the "EXPAND" pin.

I'd sorta complain about using a Z80 for that too, unless it performs notably better than the SNES CPU it doesn't seem all that interesting. The video and sound registers might as well be mapped to the SNES directly, so it can get straight to it. I think a better CPU would be something like the MIPS or ARM. They should be fast enough to emulate a Z80 or 6502, if one didn't want to program in native assembly or C.

Even better would be using an FPGA to recreate all those (or create new) functions in a single chip.

Sure any of this stuff is possible, but just depends on what you want to do with it.

There are those clone systems around that include an SNES and Genesis inside, maybe there would be some way to modify it and bridge the systems?

Find the 28-pin female socket connectors for the expansion port, sell a hundred to me (with profit markup), and I'll tell you anything you want to know about it =)

Without the connectors, you won't be able to get anywhere. They are impossible to come by.

Ok, the specs were pure shite, it's because i saw some threads discussing Full Motion Video on SNES, especially byuu, who wrote that interesting add-on to play FMV. And so i thought a SNESCD would do a great job. What do you guys think? Pure dreams or maybe true?

Reply to byuu:
Getting the 80th!

EDIT: What a good time to have my SNES broken, eh? Lil' bastard turned from NTSC to PAL 'cause i used some obscure f-zero cart! Video here, please help!

Memblers wrote:There are those clone systems around that include an SNES and Genesis inside, maybe there would be some way to modify it and bridge the systems?

Genintendo? Or Super Drive? Sounds great...

A SNES doesn't somehow change from an NTSC model to a PAL because of some game you played.

Maybe you got connector dirty with that cart. Or maybe you physically broke the connector.
Or it could be some other hardware failure unrelated to plugging in that cart.

Sorry guys, but i can't stop posting.

It looks like my SNES is with a very old cart slot. I also upped an image of the obscure f-zero cart here:

Seriously, and it wasn't even criminal market. Strange enough, in Brazil our carts are similar to the American ones, and this looks European, here is the picture of it open. And now, we can see the cart broke. Anyone can tell me if my SNES can still be fixed? Also, the EEPROM was REALLY cheap. Doesn't F-zero uses a special chip? Forget it. I didn't find any special chip on it. just a Taiwan made EEPROM with FO written on it.

Sorry for big pics!

mic_ wrote:A SNES doesn't somehow change from an NTSC model to a PAL because of some game you played.

Maybe you got connector dirty with that cart. Or maybe you physically broke the connector.
Or it could be some other hardware failure unrelated to plugging in that cart.

So i should try what? You saw the pics? The cart pins are black. How do i clean my connector?

You wouldn't happen to be (possibly related to) this guy, would you?

byuu wrote:You wouldn't happen to be (possibly related to) this guy, would you?

Not a chance. I don't even know this guy. I just want help to fix my SNES, and try to make games for NES and SNES... Oh boy, i miss playing "S.T.G. Strike Gunner"...

edit: Oops, got the title of the game wrong!

mic_ sure is right. The freaking cart made my connector as dirty as Leisure Suit Larry. Oh noes! What do i do now? Which tools i must use? (Please, don't say SNES Cleaning Kit, in Santos, no way to buy it!)

Edit/add: Interesting though the system's running on PAL-M mode, the sound is not slowed down. The APU and CPU work just fine, but the GPU's got problem.

Shiru wrote:So, other CPU, other audio, other graphics - completely new system. How this would relate to SNES then?

The original PlayStation was originally a CD drive for the Super NES before Sony retooled it not to require a Super NES.

Memblers wrote:I think a better CPU would be something like the MIPS or ARM.

And guess what's in the original PlayStation.

IvanDSM: Did rubbing alcohol (isopropanol 70%) on a cotton swab work?