Popolon Musical Memory Mapper
This page was last modified 18:29, 26 February 2020 by Mars2000you. 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).

Additionally it has the following features:

  • A SN76489AN sound chip used in various game consoles of the 80s built-in.
  • A write protection function and the ability to manage its memory regardless of other memory mappers.
  • 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 compatibility with MSX1.

Many memory mapper cartridges support reading the mapper registers to support some non-standard compliant software which attempts to do so. The first version of MMM is a memory mapper does not provide this ability. The second version of MMM (chrome case) does allow mapper read-back to be enabled. By default it is disabled.

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


  • RAM: 1024kB
    • Memory mapper with MSX1s support and configurable to specific 16K mapper
  • SN76489AN inside (I/O ports: 3Fh)
    • Disabled by default

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 (Memory mapper RAM tester by Marteen)
  • SofaRom (MegaROM and ROM loader by Louthrax)

External Links