The Pokey Printer Port Sound Card As many of you know I released an 8-bit Atari emulator for IBM compatibles called Pokey. During the writing of this emulator I found out that Atari sound was the most difficult thing to emulate. The Pokey chip (sound chip in the Atari 8-bit computers and 5200 game console) has four channels with distortion levels on those four channels. Tough to emulate on your most common IBM PC one channel sound cards. So I decided to put an 8-bit Pokey chip on a small circuit board and plug it into my Printer port to see if I could obtain true hardware sound. The results were awesome since we are using the same chip as in the 8-bit. And the sound capbilities take little overhead away from the emulator software. Im releasing this information to everyone out there who wants to build their own PC Pokey Sound card. Im also releasing this information to all the Atari emulator developers out there: Xlit, Xformer, ACE, Rainbow, Atari 800 (David Firth), VSS 2500, etc. Ive gotten good responses from most who are willing to add support for the Pokey card in their emulators. Now before I go into the card let me say that I am not liable in any way for any damage this circuit does to your system. The circuit is working well for myself and a few friends, but I don't guarantee that it will work for you. As always make sure you check your wiring thoroughly before testing this on your computer. I am also not responsible for any misprints in the schematics and other info. I have checked this as best I can....... If you are not electronically inclined stop now! One other note. This ciruit works amazingly well with all the systems I have tested it on. These systems are very fast PC's (p166,p133). I would recommend an ECP or EPP parallel port for this circuit. I haven't been able to test the sound quality with my Emulator on my laptop 486 DX250 since my emulator is too slow on that system. If you don't have a fast system you might want to look into the PC Card version of Pokey (see below). Its a safe bet to say that if my Pokey emulator runs well on your system and you have an ECP/EPP parallel port you are good to go. If other developers add the Pokey card to their systems, the same should hold true. I will be giving info to the developers on the PC card version if I actually build some up to sell. See the file "parts.txt" for a listing of parts needed to build the card. All items are common items you can find at Radio Shack, JDR , etc. The only obscure device in the bunch is the Atari Pokey chip. After assembling the board based on the schematic (pokey.bmp) test your circuit for accuracy. Look for shorts (especially across ground and +5 volts). Once you have it built you can either try it with version .61 or later of my 8-bit emulator Pokey (with the -psound option). Or use the enclosed ptest program to test it. The ptest program is pretty easy to use. Plug in the pokey card to your printer port (with your computer off!). Apply power to the pokey card and turn on your PC. Run the ptest program. Select any of the four middle C channel commands to hear a middle C note being played on that channel. If you hear a sound your in business. If not go back and check your wiring. Also the schematic has an item J1 on it. This is the DB25 pin connector listed in the parts.txt file. The others should be easy to identify. ----------------------------------------------------------------------------- If your not brave enough to build a pokey card, or your system is slow, or you don't want to give up a printer slot, you might be interested in a PC card version of Pokey. Im toying around with the idea of having some built and selling them to users. If your interested in buying one of these please drop me an email and let me know. Also let me know what you would be willing to pay. This would be an actual etched circuit board (8-bit ISA card). It would have a phono plug on the back to go straight from it to your sound cards line in. Right now I am thinking they would need to be around $35 - $50. Please drop me an email and let me know if you would be interested in one and how much you would be willing to pay for one. If I get enough interest I will have some boards made and make them available to all. I am also going to give the programming info for this board to the above mentioned developers so they can include this option also. ----------------------------------------------------------------------------- Mike Hill 7976 Strawberry Hill Lane Maineville, OH 45039 mhill@one.net http://w3.one.net/~mhill