This Sega Genesis RAM Cart Could Take Homebrew Development To A New Level

So, it will expand the capabilities of the Sega CD and 32X, but not the Genesis itself, as in Genesis cartridge games cannot directly use this extra RAM chip too, correct?

How is this connected to the Genesis?
The Sega CD uses the expansion port while the 32X used the cartridge port, so how do you make an upgrade supporting both devices?

@KingMike well you can't run either system without a Genesis/Mega Drive.

@KingMike it's a ram expansion for the Mega CD not for the Mega Drive so the cartridge port since it says it's a cartridge. Its pretty much the exact same concept as the Sega Saturn ram expansion since you cant use the port to do anything else at the same time.

@RetroGames there's an adapter for the side port that flash carts can use (like the MegaSD). Maybe that's what they mean.

@Zenszulu That's what I was thinking. Something of a sort similar to the Sega CD Backup RAM cart. I know that was an officially released cartridge which acted as a removable Sega CD memory card. It needed a certain pin on the cartridge connector set to tell the console that the cartridge is not an executable program, don't try to run it.

Very interesting topic. Perhaps worthy of a deeper dive article?

@KingMike The easiest way to look at it as the cartridge slot cant do two functions at once so it can be used for either being a rom. cartridge, ram or as you suggested as a memory card. One feature that was never used during the Mega Drive's commercial life was that you could have had a lot of data on a cartridge to load in faster while also having stuff at the same time on CD that loaded a bit slower to make games load faster in general and store any music, cutscenes and voice acting on CD. The Saturn did a similar thing with KOF '95. It was probably down to the cost and how few people would but games that were on both a cartridge and CD that would only function together.

@Zenszulu I do remember the aftermarket game Pier Solar boasted it was a cartridge game which could optionally utilize the Sega CD for an alternate soundtrack. I recall they encouraged players with the hardware available to burn a CD and play with it.

@KingMike They did I have the official CD they released. It would have been good if they added some other stuff on the CD other than just music an all in one system probably would have taken advantage of it more if it sold well enough. But I do understand why publishers at the time would have dismissed a game that used both at the same time but for optional enhanced sound tracks I think it may have been fairly popular as it would double up as a regular audio CD for those without a Mega CD.

@Zenszulu Now I remember that back in the day, EGM ran a rumor of Capcom considering a chip+CD combination for the PC-Engine version of Street Fighter II. One problem then is that Capcom would've had to bake in their own CD firmware into the game, as the standard firmware takes up the chip game slot.

And even as it was, SFII needed its own unique card as it exceeded the (roughly) 16 megabit (2MB) chip ROM maximum (minus some space occupied by RAM and IO) the PCE CPU's built-in mapper was designed to support. (I think the 20mbit SFII was the only released PCE or SuperGrafx HuCard/TurboChip game over 8 megabit).

How it work, It's in the description of the Github
Make sure the lower switch on the cart is set to "boot off the CD" position. Write the ISO file of this project to a CD-R and boot using the SegaCD addon.

After initial loading, the program will list files it was able to find on the CD. Select a ROM file from the CD and press A to write it onto the RAM cart. Pressing B will verify ROM/RAM contents with the selected file.

To boot off the previously written ROM, you need to toggle the lower switch to the off position and power cycle the console. Pressing the RESET button on the console will not work!