Well if I have some news:
NesBox:
http://pixelretro.hebergratuit.net/NesBox/snes.html
rom:
http://www.mediafire.com/file/9ton5dtzs562fb6/main.smc
I don't guarantee that on NesBox the sound is well restored.
The start button to play music.
The select button to pause.
The Y button to reset to zero the music (a loop).
I had to create a MIDI converter / SNES, and I code the SPC700 to a partition that bed +I/O.
Normally when using the 8 channels + the good sample + good modulations, hopefully play good music, but as you can imagine lunch offers me only partitions, samples + the modulations of sound, it is I who should do it (or find a good composer / musician who cares).
I manage all the sound modulation, the transfer of samples / partition on the SPC700 and other small effects.
The version of my driver is at version 0.7 (0.8 when playing sound will be completely finished), 0.9 when you could 'add' different modulation, version 1.0 when my driver will was tested and approved
The SPC700 is limited to 64K here's how I distributed:
PRG : 0x0200 -0x16FF
SampleDIR : 0x1700 - 0x1AFF
track : 0x1B00 - 0x3FFF
Sample : 0x4000 - 0xFDFF
RAM : 0xFE00 - 0xFFBF
So my driver did so 5ko, the rest will have to transfer ROM / SPC700 , transfer takes me 1% CPU for 2 bytes.
So if we tranfer in game , if we take 50% of this is 100 bytes per frame (or 6000 bytes / second)