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 Yamaha YM2413 sound 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 folling software that is a alternate tool to backup and restore the SRAM content:

PAC Saver ver1.05 by AtoC. (Source code)
Nandemo SRAM Saver by Tiny Yarou - Tool for MSX turbo R - it uses the PAC or internal SRAM instead of a Data recorder to save.
ESE-PAC tools

This firmware is in Japanese but you can translate it by changing the Rom. The patch can be downloaded from downloads here.

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 non-rechargeable 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 by soldering a new one (type: CR2025 or BR2025 Lithium 3V). Confirmation is needed about battery pins type. Be careful not to overheat the battery when soldering it, and put on safety glasses because of the risk of explosion with heat.