Arcade Machines Without a CPU

[Mr. Brow]

Lately I’ve been exploring the very early history of arcade games, where the game was a product of discrete integrated circuits rather than microprocessors.  I mean games like Pong and Breakout.

 

Does anybody own functioning units of this kind?  Have you opened them up?  Perhaps even repaired them?  It’s amazing to me the complexity of the circuits that went into a game as simple as Pong.

[mr_me]

You mean discrete components before integrated circuits.  Eventually atari and general instruments put it all in an integrated circuit chip.

[simbalion]

I think Pong had integrated circuits as well as Breakout. Now Computer Space, that was early and discrete circuits. I got to open one up years ago and that was neat. Some games used discreet circuits for sound a bit longer if memory recalls. Perhaps a better question is what games were made before the microprocessor chip was first used.

[Mr. Brow]

16 minutes ago, simbalion said:

I think Pong had integrated circuits as well as Breakout. Now Computer Space, that was early and discrete circuits. I got to open one up years ago and that was neat. Some games used discreet circuits for sound a bit longer if memory recalls. Perhaps a better question is what games were made before the microprocessor chip was first used.

From what I’ve read, the first arcade game to use a microprocessor was Gun Fight in 1975.  

 

It’s not complete, but the list of games emulated by the Discrete Integrated Circuit Emulator (DICE) is a good starting point:

 

http://emulation.gametechwiki.com/index.php/DICE

[almightytodd]

Most (if not all) of the early video games used integrated circuits but not microprocessors. Computer Space used the 7400-series Transistor-transistor Logic (TTL) chips. These chips were capable of generating results of the most rudimentary Boolean logic functions (and, or, exclusive or, not-and (NAND) not or (NOR). Microprocessors such as the Intel 8080, the Zilog Z-80, and the MOS 6502 were not cost-effective until the mid-1970s.

[mr_me]

The last and most complicated might be Monaco GP by sega.

[Zoyous]

2 hours ago, mr_me said:

The last and most complicated might be Monaco GP by sega.

That was one of the first games I ever played as a young kid. So, many years later when MAME came along, I naturally went looking for it, couldn't find it, and subsequently learned of it being a discrete logic game. That's pretty awesome!

[ChildOfCv]

6 hours ago, simbalion said:

Some games used discreet circuits for sound a bit longer if memory recalls

Well, many used specialized components, maybe a few used all discrete components.  I remember looking at the Donkey Kong schematic.  Jump Man's foot noises were a frequency-modulated oscillator centered around his foot frequency (maybe 600Hz or so).  So if it were on constantly, it would sound like a rapidly cycling siren.  But instead we hear a time-sliced portion of it.  In addition, it had a pull-up linked to being turned on which bent the noise frequency up.  So this is why every footstep has such a unique sound.  IIRC it was built from transistors and oscillator trimmings.

 

The donkey stomp was a linear feedback shift register that cycled at a low frequency.  It also had a transistor to control the amplitude attack/decay rate.

 

But it also had an audio microprocessor and a ROM chip that did the majority of the sound FX and background music.

[mr_me]

7 hours ago, Zoyous said:

That was one of the first games I ever played as a young kid. So, many years later when MAME came along, I naturally went looking for it, couldn't find it, and subsequently learned of it being a discrete logic game. That's pretty awesome!

Sega made a faithful remake of Monaco GP for the Saturn.  That might be the  closest thing to playing the original game at home.  I doubt the original machine will ever be emulated.

Edited January 4, 2020 by mr_me

[Zoyous]

3 hours ago, mr_me said:

Sega made a faithful remake of Monaco GP for the Saturn.  That might be the  closest thing to playing the original game at home.  I doubt the original machine will ever be emulated.

Did they really? I should track that down, I do have a Saturn with a Play Action Replay cart. Thanks for the tip!

[mr_me]

There's also this more recent fan made Monaco GP remake for windows/linux.

http://forum.arcadecontrols.com/index.php?topic=134445.0

 

----------

I played the old arcade game in the old days too.  I looked for it in the early days of mame, but didn't understand why it wasn't there until a couple of years ago.

Edited January 4, 2020 by mr_me

[Zoyous]

Oh, wow, this looks very accurate and seems to be a true labor of love. I'm just watching the attract mode so far and it looks phenomenal!

[doubledown]

The proper way to enjoy Monaco GP is an original Cocktail cabinet ?  One of the coolest looking cocktails of all times in my opinion.  

 

 

I currently have a Turbo upright, and I've been on the lookout for one of these for a little while now, but not sure if I'll ever get my hands on one.  There is also an FPGA project going on for Monaco GP so that old cabinets can be brought back to life.  Not my project, I just check in on it every now and then.

[chopperthedog]

There's some other cool TTL coin op stuff that wasn't exactly a video game. I have an Electro-Dart wall game from 1971 in my collection, main pcb is in the left unit and large multi pin cable connects to right unit for lamp operation. Fun game, on wireless remote you press and hold button while watching the animation of your dudes arm and release button/dart at right time to get bullseye or lesser score based on timing. There's no sound, you just have to picture a couple old dudes sitting at the bar of the VFW in 1972 passing the remote back and forth with 50¢ bets on each game. I've been meaning to shoot a good video of mine in operation, there's a couple other blair witch type vids on the tube already if you want the gist of the game. Wonder how many folks here have even heard of "wall games".

 

 

good day.

[Mr. Brow]

I did a write-up about how the graphics were generated in some of these early arcade games. I know there are many here with more technical know-how than myself, so please let me know if I'm misrepresented anything there.

 

I was surprised how much information I was able to glean just from the service manuals for these early arcade machines.  Some of them go into a lot of detail about how the games work.  Also, this document was a fascinating resource on Pong: http://www.pong-story.com/LAWN_TENNIS.pdf.  I'm not experienced enough with TTL to follow all of it, but it's still an interesting read.

[mr_me]

The write-up nicely shows when some primitive animation was introduced.  I like the Atari Hi-way example where you can see that a timer is simply used to not only distort the car but shift the road for a vertical scrolling affect.  In the previous year Atari also had Gran Trak which had more sophisticated sprite rotation but a static track.  The Gran Trak / Indy / Sprint machines from Atari were quite common.  Then in 1977, cpu based Super Bug added multidirectional background scrolling.

 

Although some of these early driving games look primitive, Gran Trak in 1974 had a steering wheel, four position gear shift, brake and gas pedals.

Edited January 18, 2020 by mr_me