RetroWave OPL3 Sound Card (USB/SPI) with ao486? (Similar to External MT32-PI?)

[sofakng]

Does anybody know if it's possible to add support for something like the RetroWave OPL3 Sound Card to the ao486 core?

I'm also interested in sound emulation as accurate as possible and this "sound card" is basically an authentic YMF262 chip with an SPI I/O extender. It's also Raspberry Pi compatible or they sell a compact PotatoPi Lite to interact with the YMF262 over USB. (there is support for DOSBOX-X to provide FM sound using this setup)

Between the MT32-PI and this project, it would provide authentic MT32 and OPL3 sound which would be fantastic.

[jordi]

It might be even easier to have OPL3LPT/OPL2LPT as a parallel port implementation looks simple from the outside. Same compatibility as well.

[sofakng]

That's also a good idea but it looks like it uses 11 of the 25 pins on the parallel port (DB25) connector. I don't think the MiSTer has that many more available with everything else it uses?

[jordi]

That's also a good idea but it looks like it uses 11 of the 25 pins on the parallel port (DB25) connector. I don't think the MiSTer has that many more available with everything else it uses?

But I guess it's feasable and easy to do just with any USB <=> LPT adaptor, which are extremely cheap.

[MorkMikael]

would it be possible to use it on top of the mt32pi and run it on a raspberry pi to run the mt32pi and RetroWave OPL3 Sound Card on the same pi ?

[sofakng]

That would be awesome, but there are many problems...

1) ao486 core needs to be modified to send OPL data to user-port.
2) mt32pi needs to be modified to recognize data and send to RetroWave OPL3.
3) RetroWave OPL3 card outputs to 3.5mm jack and has no interface to send data back to ao486 core.

Unfortunately I'm not too hopeful on accurate OPL emulation with ao486 core. Everybody I've spoken to says it's a big project to develop an OPL FPGA implementation and the ao486 doesn't have room anyways.

Perhaps something running on the Linux side of the MiSTer (ie. Nuked OPL3 emulator) and communicating with ao486 would be the next best idea?

[the_muteKi]

I feel like if you're going this route you'd need to set up nukedopl3 on the pi side, because it's pretty cpu-intensive, but I can't say I've looked into this at all. Frankly the core has a better opl3 implementation than, frankly, most sound cards post since the Soundblaster-16, so I've never been too put off by it. That said I haven't used adlib tracker on it either so I haven't been doing anything too fancy with it yet.

[caad]

What are the parameters for the communication with an OPL chip exactly? Why wouldn't a USB connection suffice, is it due to timing requirements?

[juami]

Mister could handle Retrowave OPL directly without RPi.
Retrowave uses simple SPI control with /CS. ( it uses MCP23S17 IO expander to control YMF262 )
we need to change User Port of Mister into 4 line SPI ( CLK,MISO,MOSI,/CS ).
SPI protocol is simple ( we can find protocol info from Retrowave github source code and DOSBOX-X code )

[ferropop]

Would kill for RetroWave support in the ao486 core.

If you look at how ScummVM/dosbox-x have added support for the RWopl3 - they seem to have (simply?) redirected the commands intended for the Nuked emulation to the device, given that it will respond identically given that it's literally a real OPL3.

No need to redirect RW output internally like the MT32-pi -- using the RWopl3's 3.5mm output (just like ScummVM/dosbox-x) is definitely good enough! Outputs are cleaner than the DE10's by a mile!

[ferropop]

Bump!

[ferropop]

Would be amazing, and they make their documentation freely and easily available :

https://github.com/SudoMaker/RetroWave

Does this seem feasible?