Need a DIY MIDI FM synth module

Topic actions

Reply 20 of 21, by kb77

User metadata
Rank Newbie
Talking_Sword wrote on 2020-07-24, 04:51:

I'm not sure, how the Arduino can help me with programming. It's just a development board for a AVR microcontroller. Also, my musical abilities sucks just like the programming skills. To create musical synthesizer firmware, knowledge of musical theory most likely needed.

Error 0x7CF wrote on 2020-07-23, 18:14:

The weak documentation for the YMU762 is a real shame, it could be a lovely synth for homebrew computers. It's certainly better than the YMF825.


OK, I know this topic was not active for few months now - but... Well, just check my channel: https://www.youtube.com/channel/UCRRECROYDILhQ00W-XV6uOQ

Ymf825 (SD-1) is a close relative to Mobile Audio chips. Comparing to Ymu762 (MA-3) - is is missing the sample playback capabilities and has no instrument ROM (MA3 has the standard MIDI set definitions plus few percussion samples in the ROM, also has some RAM for user defined FM instruments or samples). Voice register map is almost the same, waveform numbers (except 3 in MA-3 that are using samples as sound source), algorithms, ADSR, MULT etc - all matches.

So I tried mapping OPL2 to MA3 😀

What is a pain in the back: a simple change of the lower 8 bits of frequency register in OPL ($A0-$A8) translates to a dozen or so writes and reads to MA-3. Setting note on - even more.
For FM synth it is not a problem possibly, I could give it a try and make MIDI synth out of it, but well, as I did it previously with Vs1053b:
https://soundcloud.com/konrad-b-694217055/c64 … a2-3-on-vs1053b
https://soundcloud.com/konrad-b-694217055/c64 … dash-on-vs1053b
And then, when you compare it to the way it sounds on the real MA-3 ("Ninja" here again):
Well, I would rather not base any MIDI synth on MA3. At least not as the main or the only sound chip.

Reply 21 of 21, by Adriaan

User metadata
Rank Newbie


Made this midi controlled rack, two YMF262 (6 voice, 4ops) modules and a wavtrigger.
Currently I am looking for info about the YMF704 to program it with an Arduino or BluePill.


  • Filename
    File size
    971.79 KiB
    File license
    Public domain