Converting An Atari 2600 Into A Home Computer; Did That Ever Work?

[Tony] posted an interesting video where he looks at the Atari 2600 and the way many companies tried to convert it into a real home computer. This reminded us of the ColecoVision, which started out as a video game but could expand to a pretty reasonable computer.

It might seem silly to convert a relatively anemic Atari video game into a computer, but keep in mind that computers were pretty expensive in those days. Not to mention, the Atari itself was a fair investment back then, too.

There were four options [Tony] found, although none of them seemed to be very popular. One looked like a cassette player that plugged into your cartridge port and a keyboard port for a cheap-looking keyboard. [Tony] thinks it, along with the “piggy back,” never actually made it to market.

Atari also got into the act with the Graduate. For $79 you got 8K of RAM and a membrane keyboard. There was a big public relations push including a very period TV commercial you can see in the video.

Apparently a dispute between Atari and the actual designers of the Graduate, caused Atari to kill the project with no sales. So far, of the three [Tony] covered, none of them were sold to the public.

The fourth one, CompuMate, was sold for $79. You would get some extra memory and an odd-looking membrane keyboard along with a cassette port. If you want to see the guts, fast forward to 13:30. Like many period computers, it will start up at a BASIC prompt. Unlike many other computers, it would also play Twinkle Twinkle Little Star.

The screen resolution was very poor. Apparently, the flavor of BASIC used by the CompuMate isn’t very well documented. A 100 line program fills up the memory which is funny when you think of how much memory your PC or even your phone has today.

It is hard to realize that the days when this kind of add on might make sense was not that long ago. You can wonder what the computers of 2080 will look like.

If you want to write native, there are ways to do that with a bit of work. There are plenty of ways to get the equivalent of a 2600 — and more — in a much smaller package now.

17 thoughts on “Converting An Atari 2600 Into A Home Computer; Did That Ever Work?

  1. The Atari 2600 only had 4K of program space, and no write line put out to the cartridge slot. I spent some time learning to program it in the late 1990’s. The video system is so primitive that displaying a few lines of text each of 12 characters or so takes nearly all its processing time. That’s right, processing time, because the CPU has to draw the display line by line. It’s really unbelievably primitive.

    The Colecovision by contrast was a real Z80 based computer with a separate TI video system with its own RAM, and was quite sophisticated for its day. I used an Adam conversoin kit for several years for word processing, a thing at which it excelled with its super cheap daisy wheel printer in a day when may publishers wouldn’t accept a dot-matrix printed manuscript. Coleco may not have had the long-term success Atari had but their system was a good ten years beyond the 2600 and if they hadn’t had so many production problems delaying the intro might have given IBM a run for its money in the early 1980’s.

    1. 4k of rom directly addressable, and more importantly 128 bytes of ram. The TIA chip controlling the electron beam of the TV ran faster than the CPU too (3x? 4x?) so the code had to get everything setup mid-scan-line to be drawn.

      It’s mind boggling what the demo scene has accomplished with the thing, with music, scrolling text on 3d rendered planes and rotating perspectives…

    2. The 400 (stripped down) was meant to be the next-gen game console, but for as long as the Games Division had sway over the company, they wouldn’t allow the Computer Division to productize as a games console. Because “bonuses”.

      Coke I and Nintendo were progress, but mainly they were inevitable.

      PS- there was also 2600 Basic. Have it; abysmal and no way to save code…

      1. The stripped down 400 was sold as a console, the Atari 5200. It was fairly successful. Might be Games Division were responsible for shipping it with the famously hand-crippling joysticks though.

        2600 “Basic programming” specifically wasn’t BASIC programming! Yes it was shit. You could only enter 5 or 6 lines of code before the 128 bytes system RAM ran out. I tried to write a program to move a dot around the screen under user control. Wasn’t enough RAM to do it! It was utterly useless! If they’d maybe stuck a 4K RAM chip in the cart or something it might have been semi-practical, though even so it was a complete abortion due to the 2600 having no screen RAM, and at best 12 characters, interlaced and flickery, across the screen.

        The 2600 was designed in 1976 to play games of the day, cheaply. That meant Pong, Breakout, Combat, and Night Driver. That it lasted into the late 80s with some truly brain-twisting programming is testament to whatever their programmers were smoking. The later games, particularly the arcade conversions, were extremely shit. Though Ghostbusters actually wasn’t bad, it just happened to have screens that suited the 2600’s hardware.

  2. I remember reading a message board post where some people were trying to add a NS405-B18N that is basically a all-in-one Terminal in a 40pin DIP as the Video and I/O to make an Atari 2600 into a computer. However they didn’t get far with it.

  3. So the PCB for the cart has a 74LS122, a 74LS10, and a 74LS02. Looking at Stella’s source, it’s clear that the 74LS10 and 74LS02 are responsible for how banking works here, but I can’t figure out what the 74LS122 is doing. Does anyone have any guesses?

  4. I remember my father bringing home an Atari basic cartridge with 2 little membrane keyboard that slotted together and plugged into the joystick ports. I didn’t get to play my Atari anymore when my dad came home from work for like 2 weeks until he gave up on it.

    1. I remember Atari Basic. I had it too. couldn’t save anything and you were limited in the scope of what you could program. Good primer for a kid, but other than print statements you weren’t doing much.

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