Hi all

I've been messing about with the SFX Sound Expander for the C64 recently.
Have read pretty much all I can find.

Using the documents widely available from Lee and Totto (I think!), I cobbled together a rough BASIC program which produces a noise.  All's fine.

I'm trying to use Percussion mode now and am getting noises which sound like someone spitting!
Can anyone give me some pointers as to how to trigger the drum sounds available on this chip?
Ideally, what is the sequence that sets the chip into percussion mode and triggers say a snare drum?

TIA

Spikes

i cant help you but i would love to follow your work on this.

I think your best bet is to disassemble some software and look how they did it. I don't know anything about the YM3256, but if it's anything like the OPLL, you have to put it into percussion mode, set some frequency values for the voices that are used and then just set/clear bits of a single register to trigger the different drums. I think the OPL2 works this way, too.

Yes, that is exactly it!  But unfortunately for me, it doesn't seem to want to go into Percussion mode, let alone sound like a snare drum!

I'll try to post the BASIC listing of what I have done so far.

Thanks for the input though guys, someone on here will know the answer...I hope!

Mega bump because I just got one of these and am upgrading it to YM3812.

Stuff here:
http://cbm-hackers.2304266.n4.nabble.co … 07070.html
And here:
https://code.google.com/p/c64-sfx-cartridge-player/

This guy made an AdLib player. You can check it out here:
http://csdb.dk/release/?id=119462

Someone make a SID+FM tracker? Linde, can you modify SIDWizard to add FM pwetty pwease? big_smile There's basic ally NO software for this cartridge except this player and the original software which is poop. SID+FM sounds just DREAMY. I can lend my cartridge to anyone that wants to work on this.

Last edited by akira^8GB (June 10, 2013 6:21 pm)

Two things:

One: YM3526 might not have percussion mode from what I read
Two: can we have the source to your BASIC software to make a noise with the SFX cart? I need to test my cartridge and I ccan't really figure out how to make t in BASIC. How did you do the delay of 12 cycles that needs to happen before you send data to the YM register?

Last edited by akira^8GB (June 19, 2013 3:31 pm)

akira^8GB wrote:

Someone make a SID+FM tracker? Linde, can you modify SIDWizard to add FM pwetty pwease? big_smile There's basic ally NO software for this cartridge except this player and the original software which is poop. SID+FM sounds just DREAMY. I can lend my cartridge to anyone that wants to work on this.

Hehe, got your facebook bump. It would be a great combo for sure, but I don't think I'm up to the task of modifying SIDWizard. It would be great if only for the percussion mode, even.

From that adlib player, one might be able to hack together a SID+adlib player, though, for playing a precomposed adlib tuni in time with a SID song.

that would be pretty sweet, that's kinda how i'm making 3 x SID stuff at the moment. you make 2 separate files and play them together. its a slow process but the results sound great.

Although that's not ideal, it sounds pretty sweet indeed. One would just need to figure out a way to compose both matching tempos and whatnot.. Would love to have a play with such a thing if you ever make it, and if you ever need the real hardware, I can lend it to you  for dev purposes for sure big_smile

The biggest chllenge for modifying SIDWizard would be the UI, I think.

I just upgraded my SFX with an OPL2 chip and will try to create some sort of BASIC program that lets me access it. I don't feel pretty confident that I will succeed as  I have no idea of what I am doing tongue But if I make it beep I should be happy.

Confirmed: YM3526 does NOT have percussion mode.

Last edited by akira^8GB (June 20, 2013 8:43 pm)

So here is the little BASIC program I just did to test the unit slightly.

It's very simple: it pokes the Address port, which selects the register we're going to affect, and then it pokes the  Data port, giving it a value for said register. It's really so simple that even I could figure it out tongue

All data has been taken from this document:
http://www.floodgap.com/retrobits/ckb/secret/adlib.txt

Which explains how to make a note play if you scroll down. I just replaced that with a FOR sentence that does a little upward sweep.
I will expand on this to make it so I can test every voice with every waveform, but for tonight's experimentation it's more than enough and this is type-able enough for a quick test.

Last edited by akira^8GB (June 20, 2013 9:42 pm)

Talking to myself here, sorry tongue
I did this test and while in the emulator the result is a smooth sweep of frequencies, in my machine, with both soundchips, it's skippy/garbly. I got to assume something is wrong with the device and not the soundchips, but I have no idea what.

When I try the DRO player I will know better, I guess. There might be a problem in my code and/or VICE emulation might not be exactly accurate (and the real device might be more delicate/flaky)

Hello again all!

Real life got me side tracked with other things but haven't forgotten about this great cart and what I want to do with it, will try to dig out the couple of programs I wrote and post here.

Regards

Spikes

OK here is my BASIC listing, taken from the same document Akira^8gb used.  It makes a noise and that's it!

But just in case its useful to someone:

10 POKE 57152,32
20 POKE 57168,1
30 POKE 57152,64
40 POKE 57168,16
50 POKE 57152,96
60 POKE 57168,240
70 POKE 57152,128
80 POKE 57168,119
90 POKE 57152,160
100 POKE 57168,152
110 POKE 57152,35
120 POKE 57168,1
130 POKE 57152,67
140 POKE 57168,0
150 POKE 57152,99
160 POKE 57168,240
170 POKE 57152,131
180 POKE 57168,119
190 POKE 57152,176
200 POKE 57168,49

I've just looked at the datasheets for both chips (YM3812 and YM3526),
3526 says: "The mode selector enables switching between the sounding of all nine tones at one time, and of six melodies and five rhythms.  In either case, the tones can  (be) varied."
3812 says: "Mode selection of simultaneous voicing of 9 sounds or 6 melody sounds and 5 rhythm sounds is possible.  Both modes can produce various sounds."

How did you get to the conclusion that there is no percussion mode?  (I don't know, hence why I am asking!) 
What the 3526 lacks is waveforms.

Regards

Spikes

I've got tones coming out of it under assembler but not looked at a driver yet.

spikes wrote:

How did you get to the conclusion that there is no percussion mode?  (I don't know, hence why I am asking!)

I read it on the chip description in Hally's YM chips list, or maybe also Wikipedia. Also the creator of the AdLib player said so and, so far, that guy is the only person I know that has messed about properly with this chip on the C64 so I believe his words.

So unless you upgrade to OPL2 I don't think percussion mode will work. I can get your cart updated if you want! But please send me a message to my email, because I never check this website. 8gb >á7< kikencorp >Ð07< com

Last edited by akira^8GB (August 9, 2013 7:01 pm)