Over the last one and half month I have been designing, building and troubleshooting a port of the ALF MC-1 synthesizer to the Sega Master System. Why? Because it's fun, also because there's a small but dedicated homebrew community that still makes games for it and finally because the 76489 of Texas Instruments was the sound synthesizer for the Sega SG-1000 and, by inheritance also the Mark III and Master System.
There have been heavy modifications to the original design to a way that it is nearly unrecognizable. Some of the PSGs have been slowed down by half and to a quarter of the system frequency respectively, while two are left at about 3,6MHz to give the console the audio capabilities of a System E.
In order to not interfere with commercial software, the interface has been derivated and made compatible with the FM sound unit. In fact, there's prevision of adding a YM2413 in the next step.
In order to ease programming of the synthesizers, a read-only port has been incorporated in order to poll the ready signals of all the 76489 at once.
For more information about the device I am building, you can check its technical description in my website.
And here there's a demonstration video. Enjoy!
There have been heavy modifications to the original design to a way that it is nearly unrecognizable. Some of the PSGs have been slowed down by half and to a quarter of the system frequency respectively, while two are left at about 3,6MHz to give the console the audio capabilities of a System E.
In order to not interfere with commercial software, the interface has been derivated and made compatible with the FM sound unit. In fact, there's prevision of adding a YM2413 in the next step.
In order to ease programming of the synthesizers, a read-only port has been incorporated in order to poll the ready signals of all the 76489 at once.
For more information about the device I am building, you can check its technical description in my website.
And here there's a demonstration video. Enjoy!