New MSX Audio ROM Available

We have a new ROM for the MSX audio upgrade board. This new rom ensures better compatibility with Compile disk based games, support for loading programs from hard disk and configurations with slot expanders and multiple hardware configurations. Some users experiences lock-ups in some cases. We tested these configurations with a real Panasonic MSX Audio cartridge and we experienced the same problems. It’s safe to say that our new ROM is now more compatible than the original MSX audio ROM! We also included the default Philips Music Module program in the same rom. Pressing ESC during boot will start the default Philips Program. Pressing TAB during boot will disable the ROM completely. Because the new ROM is twice the size of our original rom some adjustments on the PCB are also necessary. Existing users who bought their expander PCB from SuperSoniqs may apply for the new ROM and needed parts without additional costs. Please contact for details. All new orders will go with the new ROM and adjustments to the PCB, starting today.


9 thoughts on “New MSX Audio ROM Available

  1. Hi FRS,

    The modifications in the MSX Audio Rom are done in the binary file directly, MSX-Audio and Music Module are in one 64k EPROM, in a few free bytes there is a small piece of code checking for what key is pressed, this code is copied to RAM first. After it knows which ROM to start, the right half of the EPROM is enabled. The bin files were disassembled to see where to modify bytes or add instructions but there is no real code, only the bin file itself. Since a GPIO of the Y9850 is used for selecting the EPROM, the original software has been modded to avoid overwriting this.

  2. I remember another fix. There was a mistake in a routine which is executed from FFCA, the work-around of poke -54 gives problems with DOS again. It uses some extbio functions but not the right way. I can only tell what i did by comparing the binary files at this point. I looked at it in a disassembler and put a return in the EPROM at some address where the right device id (&HA) was detected.

  3. Hi Dennis!

    I’m back on working on the MSX-Audio BIOS, and I’m looking to integrate your fixes on the next version MSX-Audio BIOS.

    But one thing didn’t make sense: You said that the poke-54,35 gave problems on DOS again. But this poke is only needed to fake the presence of the BIOS when the real one it isn’t present.
    With the BIOS installed, the POKE-54,35 isn’t needed anymore and Compile games will detect the MSX-Audio normally.

  4. Hi there, this poke is used for bios extensions and i remember DOS uses this as well for it’s own. The idea of this addres (-54 equal &HFFCA) is to let it point to a routine which handles things for your extension -and- when finished, point back to previous installed extensions like DOS2 or netwerk adapter… With a fixed poke -54,35 previous extensions don’t get a chance anymore. If MSX-Audio is the only extension, it’s no issue.

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