|(click on picture)|
| The year was
1978. Atari was at the top of the video gamming world with its 2600
VCS game console. Atari management looked around and saw a
new and potentially lucrative market just beginning to take shape. This
market was the Home Computer Market. They saw a market with relatively
few major competitors and Atari was in a great position to market a
computer of their own. They, after all, were a trusted household name,
everyone owned an Atari or knew someone who did!
So December of 1978 Atari introduced the 400 and 800 series computers. The actual computers were not delivered until late 1979 due to production problems.
The 400 was a scaled down version of the Atari 800. Introduced as an entry level computer based on the same MOS Technology 6502A processor running at 1.70 MHz with 16K of user RAM built in. It had a membrane style keyboard (not very touch type friendly) with 62 touch sensitive keys and 4 special keys to the right of the keyboard.
It stood out amongst the other computer offerings of the day with its graphics and sound capabilities. It was capable of producing 128 colors on the screen using the CTIA video processor and up to 256 colors with the upgraded GTIA video processor chip used on later versions of the computer. The 400 was first amongst the early computers to be able to display 4 programmable screen objects simultaneously called 'Player-missiles' (also known as 'Sprites' on Commodore computers). This was at a time when the most computers produced only monochrome displays or very primitive 8 color screens. The graphics were handled by a custom chip called the "ANTIC" (CTIA/GTIA). This chip was designed to work as a sort of co-processor to take the work load away from the main processor to display graphics and color on the screen.
The team that developed the custom chips inside the 400 and 800 was headed by Jay Miner who later, after leaving Atari, headed the teams who developed the custom chips that surrounded the Motorola MC68000 processor that powered arguably the most advanced computer of its time, The Amiga 1000!
The sound was supplied by another custom chip called "POKEY" and produced 4 voices for the most realistic sound production of any computer on the market at the time. Input/output was handled by a serial port on the right side of the machine. You could daisy chain a tape player, a 5 1/4 inch disk drive, a modem, or a printer through special d-type jacks. The Atari 400 could also accommodate up to 4 joysticks through ports on the front of the machine. The joysticks were of the standard type used on the 2600 VCS .
The computer was originally released standard with 16K of RAM, but unlike it's bigger brother it could not easily expand its RAM to 48K by plugging 16K RAM modules into the slots because it only had one slot. But inventive entrepreneurs soon found ways around this limitation and third party venders were soon selling expansion cards to replace the basic 16k card inside the 400 with larger ones.
The Atari 400 was one of the few computers of its day not to use a BASIC written by Microsoft, instead it used a version written in house, this made converting programs written in BASIC for other machines a bit difficult. For some strange reason the BASIC was not included in the ROM but it had to be loaded by installing a cartridge into one of the two slots under the lift up trap door on top front of the machine. It had to be inserted into the slot the same way you would a video game. By the way, cartridges from the 2600 VCS do not fit in these slots. The 400 had a built in RF modulator so no special hook-ups or costly monitors were necessary, it hooked directly to any TV.
The Atari 400 in this exhibit is one of three working models in the museum. It was acquired through an Ebay auction and added to the museum on June 8, 2000. It is complete in its original boxes and has all of its original documentation and accessories. Along with the purchase was an Atari 410 data recorder also in its original box.
|Microprocessor||MOSTEK 6502A||Standard on system board||16k|
|Clock speed||1.79 MHz||Maximum on system board||16k|
|Bus type||Atari proprietary||Maximum total memory||16k|
|Data bus width||8 - bits||Memory speed and type|
|Address bus width||16 - bits||System board memory socket type||Special Cartridge Slot|
|Interrupt levels||N/A||Number of memory module sockets||1 slots|
|DMA channels||N/A||Memory used on system board|
|Standard Features||Disk Storage|
|ROM size||10k||Internal disk and tape drive bays||none|
|Optional math coprocessor||no||Standard floppy drives||Cassette or 5.25 floppy|
|Parallel port type||no||Optional floppy drives:||external|
|RS232C serial ports||no||* 5 1/4 inch 160k||yes|
|Mouse ports||no||* 5 1/4 inch 1.2MB||no|
|UART chip used||N/A||* 3 1/2 inch 720k||no|
|Maximum speed||N/A||* 3 1/2 inch 1.44MB||no|
|CMOS real time clock||no||* 3 1/2 inch 2.88MB||no|
|CMOS RAM||no||Hard disk controller included||no|
|Video & Graphics||Sound|
|Graphics Processor||'Antic'||Sound Interface device||'Pokey'|
|Screen size - Col x Rows||40 x 24||Sound generation||4 voices|
|Resolution - Colors/High||2 / 320 x 192||ADSR capable||no|
|Resolution - Colors/Low||16 / 80 x 192|
|Max colors||128||Programming Language|
|Sprites or Missiles||4||Built in language||Atari BASIC|
|Built in M L monitor||no|
|Expansion Slots||Keyboard Specs.|
|Total adapter slots||0||Number of keys||61 / membrane type|
|Number of 8/16/32 bit slots||0 / 0 / 0||Upper/lower case||yes / yes|
|I/O||4-joystick ports||Keyboard cable length||N/A|
|I/O||1-RF output to TV|
|I/O||1-13 pin serial port|
|Physical Specs.||Environmental Specs.|
|* Height||4 1/2 inches||Operating voltage @ 60 Hz||120 VAC|
|* Width||13 1/2 inches||Maximum power supplied||50 Watts|
|* Depth||11 1/4 inches||Power supply output - volts||9 VAC|
|* Weight||5 pounds 3 ounces||Power supply output - amps||3.4 Amps|