Does Commando use the Pitfall II sound chip?

[Room 34]

I guess the subject says it all.

 

But I will go on anyway. Brevity is not my strong suit.

 

I am just wondering if the Atari 2600 version of Commando (made by Activision) uses the sound chip employed by Pitfall II, or perhaps another custom sound chip. The music in the game seems similar to what's in Pitfall II.

[Pitfall Harry]

I've never cracked open a cartridge to make sure, but it doesn't make sense to me that Commando could be using the Pitfall II sound chip because its ROM binary file works effortlessly on a variety of different Atari 2600 emulators.

 

Pitfall II is the only game which does not work on some emulators because of the unique design of its sound chip. If Commando used the same chip, I'm sure that there would be two such troublesome games for emulators.

 

Ben

[Room 34]

Yeah... that was going to be my argument against it too. The only emulator I have used is Stella for Mac OS X, and the only ROM I've found that it won't play is Pitfall II.

 

It plays Commando perfectly.

 

So... any ideas on the music generation in Commando? Seems slightly beyond what the 2600 is capable of internally.

[Paul Slocum]

It doesn't. Commando only plays two sounds at once, and one of the advantages of the Pitfall II chip is that you have more polyphony. Gyruss has impressive music too.

 

-Paul

[cwilkson]

The DPC chip in Pitfall II was intended for

use in multiple Activision games. They were

losing their competitive advantage in the

software arena, and they wanted to give

themselves a bigger edge. (and what an edge it was!!!)

 

But the crash of '84 kinda put a damper on

that. Pitfall II is the only game to use

the DPC chip.

 

BTW, the DPC chip is *not* just a sound chip.

It is a custum designed co-processor,

intended to free up some 6507 processor

cycles. In addition to the sound hardware,

there is 2K of ROM and qutie a bit of logic

to implement the "...if only the 6507 could

do that..." capabilities.

 

-Chris

[bcprs1]

Also, you have to look at the other later Activision games like Double Dragon and Kung-Fu Masters. Both have impressive music and work on emulators without problems.

[Paul Slocum]

Did Pitfall II use the DPC chip for the display kernal as well as just sound?

 

The 2600 is capable of pretty good music as is. You just have to find an set of notes that are in tune and stick to them. And for my stuff, I use arpeggios a lot to give the effect of chords with only one voice. (like yodeling ) Here's a 2600 music demo I did a while back that I plan on using in Marble Craze:

 

marble_music.mp3 (400K)

 

-Paul

[Room 34]

Replying to a couple of comments above...

 

The only late-era Activision game I have is Commando, so I have no idea what else I may be missing!

 

As for finding the pitches... I know how... er... delicate... intonation on the 2600 can be. It is great to play with the "Play Me" variations in Brain Games!

 

Also, the 7800 uses the same sound chip as the 2600 doesn't it? That explains the hilariously awful music in 7800 Donkey Kong Jr. (not that I don't love that game!)...

[Room 34]

quote:

---

Originally posted by Smart Patrol:

marble_music.mp3 (400K)

---

 

Killer! I might like a whole album of that stuff!

 

That makes me think of this!

[+rdemming]

quote:

---

Originally posted by Chris Wilkson:

BTW, the DPC chip is *not* just a sound chip.

It is a custum designed co-processor,

intended to free up some 6507 processor

cycles. In addition to the sound hardware,

there is 2K of ROM and qutie a bit of logic

to implement the "...if only the 6507 could

do that..." capabilities.

 

-Chris

---

 

How is the sound output of this chip routed to the 2600 RF output? As far as I know there is no sound-in line on the 2600 cartridge port. Or is this chip somehow driving the soundchip in the 2600?

[Paul Slocum]

It just drives the Atari sound chip. The DPC is sort of a co-processor that allows the volume registers to be re-written fast enough to generate it's own sounds.

 

-Paul

[Eckhard Stolberg]

Robert:

The DPC generates a new 4 bit sample value every time the program reads from the audio address. Pitfall 2 writes this sample value into one of the volume registers. It does this in every scanline and therefore generates an output rate of about 15000 Hz.

 

Paul:

Pitfall 2 also uses the extra ROM to store it's sprite data. The DPC allows you to position several read pointers over the data in the extra ROM that get decreased with every read. They also allow you to set upper and lower bounds. That way you can read your graphics data in every scanline with the same absolute address, without having to take care of any indices. That way you have more free cycles per scanline to generate your graphics.

 

 

Ciao, Eckhard Stolberg