Popolon Musical Memory Mapper
This page was last modified 10:44, 27 February 2018 by Rderooy. Based on work by Gdx and Grauw and others.



The Musical Memory Mapper (MMM) cartridge is a standard 1024KB external memory extension for MSX1, MSX2, MSX2 + and MSX Turbo R sold by Popolon and Repro Factory (2013~2016).

Many Memory Mapper cartridges behave as a internal Memory Mapper. The first version of MMM is a Memory Mapper of external type. This means that the registers of the Mapper are not readable via I/O ports. The second version of MMM (chrome case) allows the selection of Mapper type. Set by default on internal type.

However, it has other features:

  • A SN76489AN sound chip used in various game consoles of the 80s build-in.
  • A write protection function and the ability to manage its memory regardless of other Memory Mapper.
  • MMM initializes Memory Mapper pages on each memory bank of 0000h~3FFFh, 4000h~7FFFh, 8000h~BFFFh and C000h~FFFFh in the order 3, 2, 1, 0 at MSX startup to provide a full compatibility even on MSX1.

The cartridge contacts are gold plated. The price is around €42.


Musical Memory Mapper
MMM v1.2 PCB with bus connector
MMM v1.3 PCB


  • 1024KB of RAM
  • SN76489AN inside (I/O ports: #3F)

See the Manual for more information.

Minimum System Requirements

  • MSX1 computer, one free slot cartridge


  • CHKMEM.BIN (Utility that displays the slot of RAM, Memory Mapper and MegaRAM by LARK)
  • LRT2MSX.COM (included in SGTOOL.ZIP) allows to run Loretta no Shouzou (SG-1000).
  • Mapper Info (by Yukke)
  • MEGA16.COM (Megarom with ASC16 mapper loader)
  • MEMTEST.COM (RAM of Memory Mapper tester by Masatoshi Fujimoto)
  • ROM2MMM.COM (MSX Rom loader by GDX)
  • SG1000.COM (Sega SG-1000 Rom loader by GDX)
  • VGMPLAY.COM (Music Player for SN76489 and many other chips by Grauw)
  • TESTMAP.COM (RAM of Memory Mapper tester by Marteen)
  • SofaRom (MegaRoms and Roms loader by Louthrax)

External Links