PC/104 - DIY ISA Soundcard

Ive recently picked up a 486 66MHz based PC/104 module from ebay for the bargain price of £1.20. Its got 16mb of RAM, built in 2mb flash with ROMDOS on it, although im going to just hook up a 4gb microdrive and install stuff to that.

Anyway I had an idea for a project.. make it into a DOS/WIN3.11 based machine for running really old games on it. Problem is though it has no sound output other than the PC beeper/speaker.

So I was thinking about building something that I could build to plug into the bus socket on top. I remembered their being kits for (I think) adlib compatible cards years ago in the likes of maplins and such but cant find much about it.

Ive done a google and the only thing I can think of so far is to build a simple covox speech thing to hook onto the parallel, but from what I can gather they arent that well supported.

Other than that I guess the only other way would be to wire an ISA card to the PC/104 slot, but not sure about the voltage requirements, and also it would be bigger than the PC/104 module itself.

Anyone ever made anything like this now or then? Any help or pointers would be greatly appriciated. Most of the stuff I cant find these days is hooking old soundcards up to the parallel port on ISA-less machines

Thanks ina advance

Dan

 

Thanks for the reply

By that do you mean the extra bit they added to ISA to allow 32bit? No it doesnt.

Ive attached a picture of it. It has its own PC104 bus which from what I can gather is basically signal/voltage compatible with a 16bit ISA slot, so dont think something like that could be wired up. All ive seen around are ISA bridges/backplanes.

Thanks

Dan

 

Check the datasheet, you can normally get an ISA or PCI port on these things, depends on the intent of the embedded board though. Normally they don't have any sound capabilities at all (I've got 5 or so embedded boards and none have sound)/

 

I've had a flick through the datasheet and this one is just 16bit ISA. I might just pick up a cheap SB compatible card and wire it up but fancied knocking something up myself but it doesn't look all that viable. Just wanted to keep the footprint small as most soundcards I have looked at are larger than the PC104 module itself.

Thanks again

Dan

 

In theory it would be easy to make a adlib compatable soundcard as it's only the Yamaha YM3812 soundchip and the YM3012B digital dac plus a few 74LS chips to do the port decoding plus some kind of amp. The Soundblaster part is harder to do as the original used a 8051 microcontroller and a number of chips for decoding but it's possible to do. You could do a covox compatable port easily using a simple DAC or a resistor network.

 

I have a 233mhz PC-104 board with vga and sound, 128mb sdram.

It has a slot on the back for a microdrive/CF card. Worked great when I installed worms2 on it

$20 and it's yours

 

If he doesn't take that, I will...

 

Hi marshallh, thanks for the offer but im gonna pass, I feel like a challenge so if you want to sort something out with alchy,

Going to knock up a covox with a DAC if I can lay my hands on a suitable DAC or the resistor ladder jobbie if not. Alphagamer has also kindly mailed me some ISA cards at postage cost so got those to play with too.

The idea is to make this as physically small as possible.

The module also has ethernet onboard but requires an external transformer, so will have a go at gutting an old network card and getting that working if possible.

Ill post more as I get on with it.

Dan

 

The covox speech thing is supported by just about 10 dos games. You're much better off getting a soundblaster card. Some kind of adapter should work fine to interface it with the pc-104 board.

 

The funny thing is that about EVERY soundcard out there will be bigger than the pc board ^^
Use a Gravis Ultrasound Max for full size awesomeness and great sound!
It will look like the insides of one of these arcade machines with voodoo graphics cards inside them