Use of POKEY(s) in Atari Games Arcade Machines

[José Pereira]

Just came into this one and just at the first second it shows the technical details of the Arcade Machine:

-> 6502 at 1,78.... but other at 10,......

-> And then 2POKEYs to give stereo and one YM2151

This Thread it's just for the sound:

"How this sound is possible with POKEY (even two to get stereo)? Is it the YM?"

 

But this YM sure isn't the Z80/ST one, or is it?

 

And how thy can join POKEY and YM?

How is the coding?

6502 Assembly?

 

:? :?

Edited August 29, 2011 by José Pereira

[Rybags]

The audio is just mixed external to the chips. All XL/later Ataris do it, keyclick is mixed with Pokey audio, so there's nothing too magic there.

 

Pokey can run at different speeds, Atari arcade usage might be anywhere from ~ 1.2 to 1.79 MHz like the computers.

 

The later arcade games often have asynchronous bus speeds (ie different) between different parts of the system, e.g. 8 MHz for the CPU, 3.59 for the video, 1.6 for the sound.

 

Some arcade games use multiple CPUs, often the lower spec one will be to run the sound. I would suspect the main reason for this would be for smooth playback of samples.

 

The CPU/s used aren't really relevant. Pokey, YM and many other sound chips used in home/arcade systems can be interfaced to all manner of different CPU types.

 

From the end product POV re normal chiptunes, the CPU used isn't really relevant - at the end of the day all it's doing is storing numbers into hardware registers.

[analmux]

There are many different types of YM soundchips. Simple ones, complex ones. The Z80 one is simple. This one sounds a bit more like the complex Sega Genesis soundchip YM2612. (Sonic 1,2,3...)

 

What about the Pokeys? I'm not sure what they're used for in this case. At least the main music is not Pokey but YM. Maybe some of the simple SFX are played by the Pokeys, I'm not sure. Another thing might be the other functions of Pokey: serial ports, timers, random number generators, paddle control, etc.

[Rybags]

Super Sprint seems to use Pokey for the collision sound, and probably the skid too.

 

If we had the memory map for some of these games, it might be possible to use MAME watchpoints to work out what sounds come out of each chip.

[MEtalGuy66]

Some machines had Quad-Pokeys too. (4 pokeys made in one chip).. If you look in the arcade circles, these "quad-pokey" chips are becomming increasingly rare. Several people have made piggy-back boards that allow you to use 4 separate pokey chips in place of the "quad pokey"..

[fox]

Today I analyzed the ROM of Major Havoc. It's dual 6502, quad POKEY. Is there a list of machines which include (quad) POKEY ? I consider dumping their sounds to SAP files.

[Rybags]

Major Havoc, Star Wars and Return of the Jedi use 4xPokey.

 

Star Wars uses a 6809 CPU, the others a 6502.

Edited August 29, 2011 by Rybags