Super Game Boy Mod

[alanifamily]

Hello all,

Some of you might have seen some people hardwire Game Boy games into Super Game Boys to make them into SNES games (http://www.youtube.com/watch?v=JI3PSHZ3pJE and http://imgur.com/t/pokemon/dOHF8).

I would like to do something similar but instead use two Game Boy games in one cartridge.

Right now, my issue isn't with the size of the cartridge (i have plan to fix that) but how to hardwire multiple games to one super game boy.

My idea is to use a switch on the SNES cartridge to select the game you want before turning on the SNES. However, my issue is how do I send the right signals from the Game Boy games to the Super Game Boy.

I was thinking of using a series of multiplexers to send the signals from the games to the Super Game Boy. This would require 8 Quad 2 signal Multiplexers as there are 32 connectors in a Game Boy Cartridge. With the flick of a switch, the multiplexers will change their state and the signals from the selected game will be used. If this is possible, please let me know. If not, also let me know

Would you have any other ideas or suggestions?

I look forward to your responses

[Kkasino]

Just why you would kill 3 "games" to make one ?

[alanifamily]

Just why you would kill 3 "games" to make one ?

I thought it would be a neat project to do.

The only thing I am "killing" is a Super Game Boy. The games will be playable on my SNES.

[darsparx]

Just why you would kill 3 "games" to make one ?

I thought it would be a neat project to do.

The only thing I am "killing" is a Super Game Boy. The games will be playable on my SNES.

Yeah but that ruins the whole purpose of having a super gameboy in the first place(just doesn't make sense), plus you're killing a donor cart, oy vey

[Ziggy]

alanifamily PM'ed me about this and said, "I haven't received any positive encouragement or advice from other forums; only people asking me why I would want to do such a thing." I suggested to him to create a thread so he could get more input and possibly better information then I could offer alone, not so he could get flamed out. To each his own, I guess. I'm all about hardware preservation, but I don't see a huge problem with this. People do projects like this all the time, and sometimes with much more destruction. Don't judge. The donor cart would only be for the shell, so it's not like actually destroying a game like when a repro is made. Besides, he could buy a newly manufactured SNES shell (they exists) or possibly make one himself. He did say that he had a plan to fix the physical size limitations of the cart, so maybe he's gonna make his own.


@ alanifamily: Don't be discouraged. There are knowledgable members here that can help you. And welcome to Racketboy!

I was thinking of using a series of multiplexers to send the signals from the games to the Super Game Boy. This would require 8 Quad 2 signal Multiplexers as there are 32 connectors in a Game Boy Cartridge. With the flick of a switch, the multiplexers will change their state and the signals from the selected game will be used. If this is possible, please let me know. If not, also let me know

Can any one link a pinout for the GB cart edge? I'm not familiar with GB.

You don't have to switch all 32 pins on each cart. You can leave all the address and data lines connected in parallel. At most, I think you only have to switch 3 pins for each cart. Vcc (is it 5v on GB carts?), CE and/or OE. I don't think you have to switch anything else. If these connections are broken, even with the rest of the pins still connected, the cart will be deactivated. So you're only looking at 1-3 pins for each cart, that makes switching a lot less complicated.

[alanifamily]

Thanks for the welcome!

OK! I understand what you mean now.

I would connect the corresponding wires from the GB games to the Super Game Boy. Depending on which game the power goes through, that is the game that will be played.

Yes, it is 5 Volts.

Here is the Game Boy cartridge connectors:


So, there would be a switch that would switch for the power, read, write, and chip select. Maybe a 4 pole double throw switch would do it.

Would there be a chance of current going from one game into the other game through one of the address pins?

[Ziggy]

Yeah, the mask ROMs can interfere with each other which is why you have to switch more then just the Vcc. A0-A15 and D0-D7 can be left connected, that much I'm 100% sure of. You might not even have to switch the Vcc. Usually CE (chip enabled), OE (output enabled) and reset are set high or low to control the function of the chip.

I should point out that I'm not an expert. Most of my knowledge comes from reading through datasheets (which are sometimes only helpful with core knowledge) and trial and error.

Looking at the pic you linked, is that the pinout for standard GB carts. I only ask because it looks like some sort of flash cart, and I just wonder if it differs slightly from real carts. Carts with mask ROMs (not reprogrammable) wont have a write pin. It also shows "CS of SRAM" and I'm not sure what that is. Does the GB have direct access to SRAM? Or is SRAM selected through a decoder or something?

If you can't find a solid answer, trial and error usually works. You'd have to wire up the carts anyway, so you could always just wire two carts up and then play with OE, CE, etc until you find what works.

[jeffro11]

You could just use simple "Flip Flop" latching circuit controlled from a switch to select which cart you want to power up. Both carts data lines can be wired in parallel, no issue there. Probably the easiest solution.

[Hazerd]

Cool and pointless at the same time!

Back in 99, i always wished Pokemon blue and red had been made for the SNES to begin with, i still think someone should!

They were just such awesome games, i always imagined them in beautiful SNES graphics and sound, sure it wasnt until Ruby and Sapphire on the GBA that i got my wish, but it just wasnt the same.

[darsparx]

They were just such awesome games, i always imagined them in beautiful SNES graphics and sound, sure it wasnt until Leaf green and Fire red on the GBA that i got my wish, but it just wasnt the same.

Fixed