Multi Cartridge mod for Nintendo, snes or Genesis

[audman]

I remember ads in the early 90s for an device called the jukebox that allowed you to connect 6-8 games to a box that sat below your system. Then you could daisy chain 4-5 jukeboxes allowing you to play anything at the push of a button.

Any advice on how to make something similar that would allow you to create multiple ports. How would you set it up so you can say turn one game on without this mod trying to read each game simutaneously. Also what kind of power requirements do you think something like this would need. Do you think that it could run off of system power.

I know it is probably much easier to download a mame like program for pc but I already have tons of games for these systems and think it would be an cool project to make into an arcade case. Thanks for any tips in advance  

[Aidan]

Most cart designs use some pins to indicate that the console wants to address the cart. If you don't apply the relevent voltage to those pins (typically titled something like Output Enable or OE), then the cart won't respond.

Using those pins, you can put several carts together and just swap where the OE lines go to. Of course, that still limits how far you can go. For truely unlimited expandibility, you'd have to switch all the lines, which is a bit of a pain.

[audman]

what would you think should be the neatest approach to that line switching plan. Any recommendations or do you know of any plans of other attempts at similar ideas?

[Aidan]

Firstly, you have to work out which lines are output only, which lines are input only and which lines are bidirectional.

Output only lines can simply be buffered to ensure you can drive the load properly. Input only lines simply need to be switched with a suitable switch.

Bidirectional lines are a headache. You can either hope to find analog switches that are fast enough to handle digital signals, or you can use bus buffers, and hope you can produce the necessary hardware to switch the direction of the buffers when the lines switch from input to output and vise versa. The data lines (8 or 16, depending on system) are the ones that suffer this problem.