Creating an FM sound card

[Hewitson]

I am wanting to create a card (preferably in Zorro and clockport versions) which contains a YM FM-synthesizer.

It would, at the very least, support the YM3812 (many Arcade systems) and YM2612 (Sega Mega Drive). The main idea behind this is to allow ports from these systems (and others) to retain their original soundtracks.

This is something I've been considering for a number of years, but mcgeezer's Rygar port is what has motivated me to get started on it.

Whilst I am more than capable with creating the circuit for the chip, I have no idea how to interface it with the Amiga. I would appreciate any advice on how to achieve this.

[graffias79]

Very interesting. I would love a YM2612 sound board! The SN76489 is also part of the Sega audio hardware, and honestly can sound just great along side the FM chip. (Streets of Rage (1 & 2), Shinobi III, etc.) Accessible through MIDI or camd.library would be cool too.

[nobody]

What about YM2151? That would be epic.

[Don_Adan]

Originally Posted by nobody

What about YM2151? That would be epic.

Ask Chris Huelsbeck. He and perhaps Rudolf Stember too had this card for creating TFMX ST music on Amiga.

[Hewitson]

graffias79: You make a good point. In order to playback many MD songs properly the PSG would also be required.

Thanks for all the comments made so far, but unfortunately no one seems to have any idea on how to actually achieve this.

Imagine being able to create music which used the Sega PSG, YM2612, and Paula simultaneously. That would be ridiculous!

[Daedalus]

Are you looking for hardware information or software? Building for the clockport is relatively straightforward - you can get away with using a data latch on the port's data and address lines and little else, then doing whatever you like with the latched information. The timing diagrams are straightforward too, more or less standard in old PC terms with separate read, write and select lines. There's a project somewhere on Aminet for building a DIY clockport serial port that has lots of good information in it - can't think of the name of it right now, but it should be easy enough to find.

Zorro is a little more involved, since you have Autoconfig to contend with. The Hardware Reference Manual describe the Autoconfig sequences well though, so I would start there. It's essentially the 68000 bus, so slightly different to the clock port (only one read/_write signal), transfer acknowledge, changeable base address and so on. Another good source of information would be the 68000 manual. At a minimum you would need a small ROM or flash chip to report the Autoconfig requirements, and a small controller to remember the assigned address to which the card should respond and activate the relevant parts when required. The rest of the card can then be whatever you need. In practice, most projects these days use a small FPGA to implement that logic and most other functions of the card.

In both cases, standard bus interfacing techniques would apply - tri-state inputs and outputs to detach from the bus when not needed, and open-collector interrupts if you're using them.

[grelbfarlk]

I have a design for a Waveblaster interface, idea was to just pop it onto paula and get one of the newly manufactured Waveblasters. Since it's essentially just midi data going over the serial port it should work with camd. However the Waveblaster is the not an FM synthesizer, it uses soundbanks, but with the right instrument library it should basically work and sound good and not slow the machine down.

[amiman99]

Maybe do it similar way as this persons did it: [ Show youtube player ]
But, instead using USB, use the parallel port to send the data to the sound chip.
Pretty sure I have seen device like that, maybe it was for C64.

[Hewitson]

Daedalus: Thanks for the information.

amiman99: I am not really interested in a parallel port solution. However, I've been thinking a board which plugs into the Paula socket may be the best solution, as it would allow easy mixing of the FM with Paula. I'm not sure if this is actually possible or not.

[voyager]

looking at the datasheet of the YM2612, A parallel port version would not be so difficult to do. There is already a opl2 and opl3 version for the parallel port. And yes a internal version would be nice, but it will also make it more complex.

[grelbfarlk]

Originally Posted by Hewitson

Daedalus: Thanks for the information.

amiman99: I am not really interested in a parallel port solution. However, I've been thinking a board which plugs into the Paula socket may be the best solution, as it would allow easy mixing of the FM with Paula. I'm not sure if this is actually possible or not.

Well my idea was to take the output of the Waveblaster and use the CD-In connector on my SB128 or the A4000 CD-In connector. You'd have to either build a mixer onto the dongle and then get route to another speaker output.

[aperez]

This may be of interest: https://github.com/nukeykt/Nuked-OPN2

"High accuracy Yamaha YM3438(OPN2) emulator.

The YM3438 is a CMOS variant of the YM2612"

Features include:

Based on YM3438 die shot reverse engineering and thus provides very high emulation accuracy.
Cycle-accurate.
Undocumented registers/features emulation.
SSG-EG, CSM mode emulation.
Compatible with the YM2612."

[Hewitson]

An interesting project, but would just take up far too much CPU time on an Amiga. For this project to be usable in games/demos, it needs to use real hardware.

[fgh]

You probably know about ‘project XG’ ? It was released AFAIK.
Different, I know, but perhaps still useful to look up..

http://www.cucug.org/amiga/aminews/1...0-cuamiga.html

[grelbfarlk]

Originally Posted by fgh

You probably know about ‘project XG’ ? It was released AFAIK.
Different, I know, but perhaps still useful to look up..

http://www.cucug.org/amiga/aminews/1...0-cuamiga.html

Yes, that sort of thing was where I got the idea from for my adapter.

http://aminet.net/package/docs/hard/Waveblaster


It's a lot easier now that the new Waveblasters are all 5V.

I was in the process of ordering boards and the PCB company had some problem with the .brd and I never bothered to finish it. But I think it might should work, probably needs some tweaks. Should cost less than $20 to build, plus another $40 for the Waveblaster depending on which version you want.

https://www.serdashop.com/waveblaster

[Nishicorn]

This may be completely off, so my apologies if it is.

However, you might want to take a look at Serdaco's OPL2LPT and OPL3LPT devices, as those go to PC's LPT port - I think this is the parallel or printer port? I always get confused by ports, so I might be wrong.

But perhaps you could interface THAT with Amiga somehow - now, that would be cool. And inexpensive as well..

https://www.serdashop.com/OPL2LPT
https://www.serdashop.com/OPL3LPT

I mean, why reinvent the wheel, if you can just adjust it to Amiga..? (:

[Nishicorn]

Originally Posted by nobody

What about YM2151? That would be epic.

I am still waiting for THIS dream to come to reality.. if I ever can get real YM2151 to play arcade game musics, and real Atari ST to compose on, and a real MSX chip to play those Space Manbow musics, I can die a happy entity.

[Nishicorn]

Originally Posted by Don_Adan

Ask Chris Huelsbeck. He and perhaps Rudolf Stember too had this card for creating TFMX ST music on Amiga.

What do you mean by "this card"?

Some kind of YM2151 card? How do you use YM2151 to create ST-music on the Amiga? Confused..

Unless you confuse YM2151 with YM2149F.