Panasonic FS-CA1
This page was last modified 15:52, 5 October 2022 by Mars2000you. Based on work by Takamichi and Gdx and others.




The Panasonic FS-CA1 is the original MSX-AUDIO cartridge, fully implementing the MSX-AUDIO standard. The most important software feature is the inclusion of MSX-AUDIO BASIC that allows users to create songs in MSX-BASIC. Some Japanese software makers supported the FS-CA1 for music, Compile foremost amongst these. With these games, users could connect their MSX-AUDIO and enjoy an improved soundtrack similar to that of the MSX-MUSIC.

The FS-CA1 was intended for use with the Panasonic FS-A1 or FS-A1F MSX2 computers which have the cartridge slot on the top right-hand side. Due to this its size and weight (with cables attached) it's very unwieldy. If used with another MSX computer this not only makes it often stick out in a weird way, it can also cause stress on the cartridge slot. Most of the casing is empty though, and the PCB is not much larger than that of the Toshiba HX-MU900 FM-Synthesizer Unit.

The package includes ruber feet to be used on the bottom of the main unit, this to horizontally support the main body and protect it from shock and movement. It was recommended when the cartridge was used on the National FS-4600F machine or the Panasonic FS-A1 computer. On other machines, it was better to not use these feet because it would then be impossible to keep the computer horizontal.

Launch price: ¥34,800

This cartridge was only sold in Japan.


This cartridge has a built-in music program, called 'MSX Music-System', it's actually the same utility as on the Toshiba HX-MU900 cartridge, with the following differences:

  • all Toshiba references have been removed
  • the program has been adapted for a music keyboard without Multi-Sensor (that is partially emulated with the function keys)
  • the computer keyboard can be used as music keyboard (what's not possible with the Toshiba version)

According the position of the switch on the cartridge, this program will boot up automatically or not, but it can be skipped by holding the ESC key.

The menu of this utility gives access to three MSX-AUDIO songs and a music editor. You can notice that the menu screen creates some confusion with MSX-MUSIC, which is a light version of MSX-AUDIO!

From MSX-BASIC, it can be launched by entering CALL SYNTHE or _SYNTHE if you don't have already used the CALL AUDIO instruction.

Note: On the Philips NMS 8220 pressing ESC on startup to skip the integrated Designer firmware will also prevent the MSX Music-System software from starting at the same time. In this case, start it from MSX-BASIC with CALL SYNTHE.



Note: Closeup pictures of the inside can be found here.

Panasonic FS-CA1 cartridge and manual
Panasonic FS-CA1 box and content
Panasonic FS-CA1 box
Panasonic FS-CA1
Panasonic FS-CA1 back
Panasonic FS-CA1 label
Panasonic FS-CA1 mainboard
Panasonic FS-CA1 with Sample RAM extended to 256kB
Panasonic FS-CA1 cartridge with FS-A1F computer
Panasonic FS-CA1 cartridge with Sanyo PHC-70FD2 computer
Panasonic FS-CA1 cartridge (opened) with Sanyo PHC-70FD2 computer
Panasonic FS-CA1 cartridge with rubber foot installed


Panasonic Music - intro screen
Panasonic Music - menu
Panasonic Music - editor
Panasonic Music - save/load screen


The FS-CA1 is a full MSX-AUDIO cartridge:

  • Yamaha Y8950 soundchip with 9 channels of FM synthesis
  • 4-bit ADPCM channel, with max 16Khz resolution
  • 32kB Sample RAM for the ADPCM unit (can be extended to 256kB)
  • 128kB MegaROM, containing:
    • 32kB MSX-AUDIO BASIC/BIOS that can be initialised with CALL AUDIO - note: MSX-MUSIC BASIC is a simplified version of it, but this original BIOS doesn't cost you any user RAM
    • firmware
    • 64kB Sample ROM with ADPCM demo samples
  • 4kB work-RAM (for the MSX-AUDIO BIOS)
  • 1 switch to turn off the internal software

See MSX-AUDIO page for more specifications.