The Atari 400 and 800 home computers were release in 1979. They were heavily advertised by Maplin in the UK, on the back cover of various electronics magazines in the 1980s. That’s how I first became aware of them. At the time, the Atari machines were too expensive for my family, but seemed to offer quite a lot for the money.
Atari chose to use the popular 6502 microprocessor in their 8-bit computers, and clocked it at about 1.8 MHz. Standard RAM was initially 8 KB, and later 16 KB or more, expandable to 48 KB. The 800 model had a normal keyboard and internal expansion slots, whereas the 400 model had a membrane keyboard and more limited expansion options.
The sound and graphics facilities seemed quite impressive in certain respects, compared to other computers at the time. Those facilities were provided by a set of custom chips, which were named ANTIC, CTIA/GTIA and POKEY.
Later, I found out that some of the designers of the Atari machines had gone on to design the Commodore Amiga, which probably explains why I found both machines interesting. The Amiga’s chips were also given names.
Between them, the Atari custom chips provided hardware support for things like sprite graphics and scrolling. They also enabled the creation of displays with mixed text and graphics modes — all with minimal CPU overhead.
Slightly less impressive was the fact that the graphics resolution was not very high — but the ability to mix modes helped to compensate for that. The five text modes supported 20 x 12 — 40 x 24, in 2 or 5 colours. The eleven graphics modes supported 40 x 24 — 320 x 192, in 2 — 16 colours.
When configured for 4-channel sound, the pitch resolution was 8-bit. Alternatively, two voices with 16-bit resolution could be generated instead. There were other sound capabilities, such as the ability to play sampled sounds using 4-bit volume-only mode.
The Atari BASIC programming language offered good support for sound and graphics, unlike the Commodore 64 which had a fairly primitive BASIC. It also had commands for things like reading the joysticks.
String handling was different to most other implementations of BASIC, with strings being treated as arrays of characters, which is rather more like the C programming language.
Another interesting feature of the Atari computers was the Serial Input/Output bus (SIO), which allowed a number of external intelligent peripheral devices to be connected — a sort of Plug and Play system, ahead of its time.
Unfortunately, the increased complexity of the intelligent peripherals made them more expensive than those for other comparable computers.
There were data storage devices to record programs onto audio cassette or floppy disk, as well as printers, modems, game controllers, light pens and others.
In the early 80s, a few years after the original 400 and 800 models, Atari released the XL series — but these were really just attempts to reduce production costs. For that reason, I wasn’t particularly interested in them — they didn’t really offer anything new. The cost savings continued with the later release of the XE series, but by then, I had moved on to the much more advanced Commodore Amiga.
Despite never owning or using these Atari machines, I included them because of the way those Maplin adverts captured my imagination, and because of their connection to the Amiga. The Atari 800 is definitely a machine that I would like to get hold of at some point.
Do you have memories of using the Atari 400 or 800?
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