Panasoft SW-M004
This page was last modified 17:57, 21 January 2022 by Gdx. Based on work by Mars2000you and SPMNT and others.

Contents

Description

Cartridge

The SW-M004 is a cartridge called FM-PAC (FM Pana Amusement Cartridge) which was introduced by Panasonic in 1988. It is the only official MSX-MUSIC cartridge expansion and was released under the Panasoft brand, used by Panasonic for some software.

The cartridge contains the MSX-MUSIC chip with its specific BIOS (MSX-MUSIC BASIC), and an 8kB SRAM chip for saving game data (fully compatible with the PAC cartridge).

The 8kB is arbitrarily divided into 8 pages of 1024 Bytes each. A game may use one or more pages to save its data.

Some games allow you to select which pages to use, others are hardcoded to use specific pages. It is up to the user to ensure he does not overwrite old save states from the game, or save states of other games. Method access to SRAM is described here.

A hardware switch allows the user to choose between three possible output volumes for the MSX-MUSIC sound, which is mono.

Release price: ¥7.800

Firmware

The cartridge also has built-in software, which can be started by running CALL FMPAC or _FMPAC from BASIC. Here the user can listen to various demo sounds, and backup and restore the SRAM content. In the BGM (Back Ground Music) menu option, one can press TAB to get a virtual music keyboard and play the FM-PAC as a musical instrument.

You can also use PAC Saver ver1.05 by AtoC that is a alternate tool to backup and restore the SRAM content

Gallery

Hardware

Panasoft FM-PAC Cartridge scan
Panasonic FM-PAC full package
Panasonic FM-PAC cartridge
SW-M004 PCB front with removed button cell
SW-M004 PCB front
SW-M004 PCB back

Software

Main Menu
Option 1: Clear
Option 2: Copy
Option 3: Change
Option 4: Delete file
Option 5: Slot
Option 6: BGM
Music keyboard

Specifications

  • YM2413 FM chip
  • 16kB MSX-MUSIC Basic
  • 8kB SRAM (just like the Panasoft PAC)
  • Volume adjuster
  • Mono sound output
  • Built-in firmware

See MSX-MUSIC page for more specifications.

Battery

The FM-PAC (and likewise the Panasoft PAC) has a battery, without it the SRAM will not keep the contents when the system is switched off. This coin cell battery can be replaced, you need to open the cartridge and replace the battery with a new one (type: Panasonic BR2325 Lithium 3V). See this thread for details.

Typically a PAC compatible game will have one of these logo's on the box. They may also indicate which save slots they need.

PAC Logo
PAC Logo
PAC Logo, indicating the game needs slot 8
PAC Logo, indicating the game needs slot 1-4

Software using the PAC

See the list here.

External links