What is it?

A simplified version of the MSX OPM sound card, retaining the most important OPM chip and perfect sound quality. It uses only a single 5V power supply, not ±12V, so it is suitable for all MSXs, including various clones and single-chip MSXs. In order to run VGMPlay to play VGM or VGZ, you need MSX-DOS2 or above, and as much extended memory as possible.

Why did you make it?

This project is derived from the SFG-Cartridge project of the RBSC team. I used their CPLD firmware to replace the YM2148 and glue logic. I also used the SFG ROM they provided to achieve compatibility with the SFG-01/05.

What makes it special?

SFG-05 deserves a special mention here because it is compatible with the MSX version of MXDRV. You read that right. This music driver originally ran on the Japanese 16-bit workstation X68K. It was ported to MSX in 1993, so you can play MDX music on MSX. If you have MSX TurboR, you can load PDX and play PCM sound. At the same time, MXPV allows to call the system interrupt of MSX-DOS2, so it can play music in the background. You read that right. MSX can perform simple multitasking. But you need as much extended memory as possible to run these. I found that the maximum MDX cannot exceed 32KB, otherwise the player will report an error, and the MDX file directory cannot be too deep, otherwise MXDRV will complain. On the other hand, it is also compatible with VGMPlay. You can also write music with the SFG-05's supporting software. I deleted the interface of the matrix keyboard. I think that is useless and the original keyboard is hard to buy. But I kept the MIDI interface. You can restore MIDI-IN and MIDI-OUT through the pins on the board.
This project consists of two boards, the first is the MSX to RE2 bus converter board, in order to weaken the SFG-01/05, so I used a clone design of RBSC. The second part is the RE2-YM2151, this music module is completely my design, originally used in the SPFM replica project, it provides excellent sound quality and does not require ±12V power supply.

Starting SFG BIOS

To start the built-in SFG BIOS make sure that Basic is loaded and type "_musica" or "call musica" without quotes and press Enter. The BIOS should start immediately. Depending on whether the jumper is installed or not, either the SFG-01 BIOS or SFG-05 BIOS will be launched. To exit from BIOS software just reboot your MSX.