The Unimapper project by RBSC features an easy multimapper solution

ASCII8, ASCII16, Konami, Konami SCC - all these names are well known in the MSX community. These are so-called "mappers" that allow games larger than 64kb to work on our favorite MSX computers. The mapper technology requires additional electronic components to be used on a cartridge board. Those could be custom chips by Konami that incorporate mapper and SCC sound or special ASCII8/16 mapper chips. Those chips are impossible to buy these days. So, if your cartridge has a broken mapper chip, it's unlikely that you can fix it.

There are several available multimapper cartridge solutions. And each solution has its pro and contra, but most of the universal solutions require either CPLD or FPGA chips. Those chips are expensive and hard to come by these days. And they are hard to place on circuit boards. How to make things easy for everyone? There is an answer! The new member of RBSC - Pyhesty - decided to help the community. He has created a project called "Unimapper" that uses commonly available PLD (programmable logic) chips and a FlashROM. Very simple and effective solution!

The Unimapper project allows the cartridge to be assembled in 2 different variants - with 2 or 3 PLD chips. By reprogramming those chips it's possible to support 4 different mappers, that were mentioned above. The cartridge supports up to 512kb EEPROMs, so it's even possible to run Metal Gear 2 from it. Moreover, the v3.0 of the cartridge supports Konami SCC mapper and that opens the doors for DSK2ROM-converted floppy disk images to be put into MSX cartridges.

The project has been released into the RBSC's repository and is available for everyone to try. The board just needs 3 or 4 commonly available chips, a few resistors and capacitors. The chips are in DIP casing, so even an amateur can assemble this cartridge. Feel free to take a look at the project's files in the repository.

As usual, RBSC can give the permission to produce the Unimapper cartridges commercially. Please contact the RBSC's coordinator, if you are willing to make a commercial batch.

Relevant link: Overview on RBSC's website
Relevant link: Unimapper in RBSC's repository