Atari Computer Systems
 
Atari 400


In the summer of 1984 Atari, Inc was sold to Jack Tramiel (former head of Commodore) who renamed the company Atari Corp. and promised an all new line of computers and updates to the aging 8-bit line of computers.   The new computers were designated numbers to represent their memory configuration such as the 130XE had 130,000 bytes of memory and the XE stood for XL line Enhanced. At the winter 1985 CES in Las Vegas Atari displayed several types of XE systems such as the 65XE and 130XE which were later released, other systems were shown which were never released such as the 65 XEP (the "P" standing for Portable) and the 65XEM (the "M" standing for Music, the 65XEM was to have an AMY sound chip.  Problems plagued the project and it never came to market.)

Essentially the XE were not much of an improvement of the XL series.   The XE utilized technology from the 1400/1450 XL computers such as the FREDDY chip for memory management.   The ECI (Extended Cartridge Interface) was nothing more then the XL Parallel Bus Interface (PBI) repackaged to cut costs.    The keyboards were mushy feeling and the keys were white and tended to get dirty quickly, and the function keys were on a 45 degree angle making them clumsy to use at times, the 65XE's lacked an ECI all together.

Although sold as a GAME SYSTEM, the XEGS was a repackaged Atari 65XE with Missle Command built in.  However the one nice feature of the system was the detachable keyboard.   With the exception of the unreleased Atari 65XE-P Portable (Luggable) computer, the Atari XEGS was the only Atari 8-Bit computer system to ever have a detachable keyboard.




 
Atari XE
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Dave Di Giorgio  davedigiorgio@hotmail.com  on Thursday, August 17, 2000 at 18:09:56 
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The Atari XEGS

The XE Game System was simply a repackaged Atari home computer.  The only difference between it and a normal  Atari home 8-bit computer that could be purchased at the time was that it came with a light gun (which didn't exist before for the Atari), it had a detachable keyboard, and Missile command was built into the ROM set.  Missile command could be played by either detaching the keyboard or by hold the correct button down when the computer started up.

The computer was already capable of using a light pen and so the same code was used for the lightgun.

It used the 8-bit 6502 processor which always ran at 1.79... MHz.  The chip had 2^16 = 64k of byte addressable space.   This is the same chip that was used in all Atari home computers, the Apple I & II, Commodore, Atari 5200 & 7800.   Most importantly it was the processor of the sitemaps main competitor, the NES.

(Note: The Atari 2600 game system used the 6507 chip which was basically the same but instead had only 2^13 = 8k of addressable space.  It also had no VRAM and only 128 bytes of ram!)

Graphics were handled by the Antic chip which was a second CPU which ran its own special assembly commands.  The two CPU chips had to access the same memory space.  VRAM could be anywhere in this space.  The XE game system had a palette of 256 colors (16 colors x 16 brightnesses), up to 16 could be displayed at once in a single graphics mode although graphics mode mixing to get more colors was easy and common.  Also, rudimetory sprites existed.  4 that were 8 bits wide; 4 that were 2 bits wide.  Each spite was one color, but each could be a different color.  Sprites could be combined for multicolor characters.  Graphics were designed to be on a TV through a signal to channel 2 or 3 converter or on a monitor that used RCA jacks, one for video and one for 8 bit mono sound.

Sound was handled by the Pokey chip.  It had 4 independent voice channels that could either play a variety of tones and buzzers or the two channels could be combined to play 4-bit wavetables!  It arguably had the most powerful sound processing of any 8-bit home PC.

The XE games system had 64k of RAM.  It had two joystick/ trackball/ dual-paddle/ lightgun/ lightpen ports.  They used the same type of plug as a IBM 9 pin serial port.  (Note:  The Atari 800 computer had four ports.) Custom joysticks were easy to make for the computer because one pin supplied power +5Vdc, and four of the other pins were used for up, down, left, and right.  Two pins along with the +5Vdc and a 0Vdc pin were used for the dual paddle controllers that could be plugged into either port allowing a maximum of 4 players.  Hence the computer had four built in D to A converters.  I believe that the last pin was used for the light pen.

It had an I/O port for daisy chaining a tape drive, printer, plotter, or modem (1200 baud max I believe), and up to eight 5.25 inch disk drives.  Built into the console was a cartage port, which again was on all Atari 8-bit computers.  This was the form of media that the game system developed all its games for.

The game system/computer had built in Atari BASIC.

My background with the computer: The first PC I ever used was an Atari 800 computer that my school got in the 4th grade.  I loved it and so my parents bought me an Atari 800XL computer, Atari 1050 disk drive, and NEC monitor.  Overtime the chip that handled color on the computer stopped displaying green and so I sold the computer and bought a used XE game system to replace it.

I still own the computer and know a lot more information about it if you have any specific questiions.

Dave Di Giorgio 
Ride Control Systems Project Engineer 
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Barry L. Laws, Jr. bigdcaldavis@yahoo.com  on Friday, June 16, 2000 at 18:19:00 
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The Atari XEGS was basically a stripped-down Atari 65XE computer (which itself was basically an Atari 800XL with a new design).  It had a keyboard which would turn it into a computer, a lightgun, and it came with two games : Flight Simulator and Missile Command (Missile Command was an on-board game, meaning if you didn't have a cartridge inserted, it would automatically boot up Missile Command). Even though it was compatible with pre-existing Atari 8-bit computer cartridge software, it had no  
chance against the NES or even the Sega Master System. 
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