The Atari 800XL, together with the 600XL, were successors of the Atari 400/800 series and the unsuccessful Atari 1200 XL in a more compact case. They could use almost the same software, just so long as the program was written correctly, because of some slight differences between OS versions.
The 800XL had 64 KB of RAM, two joystick ports and kept all the custom chips (Pokey, GTIA, Antic) of the previous models. It also featured the new Parallel Bus Interface (PBI) providing high speed access to the system bus. The new version of the graphic Antic chip offered 16 graphics modes instead of 12 for the 800.
An enhanced version, called 800XLF, appeared in summer 1984. It was equipped with the new "Freddie" chip which allowed faster memory management, especially for graphics display. This version was released in Europe with SECAM
Alongside the Commodore 64 and the Apple II, the 600 and 800XL were among the most popular home computers.
They would be replaced in 1985 with the XE series when Atari launched the ST.
Martin Scott Goldberg says :
Regarding the comment "and can use the same software just so long as the program was written correctly", a translator disk was provided with the 1050 disk drive (the drive released with the XL series) that allowed the 600/800xl to run all older software. What it basicly did was load the original 400/800 OS over the XL one in memory.
The Atari 6502 CPU was a custom made and incorporated "74LS245" that allowed it to disconnect from address and data bus. This allowed the Antic CPU (Display processor) to access video memory while 6502 waits. I think a HALT pin was added for this purpose or something similar.
Tuesday 5th February 2013
Eric Rousseau (Canada)
Yes, the CPU is called the 6502C. The letter isn''t a speed bump designator like the A or B, it''s just a 6502 with a custom pinout. I don''t think it was ever used elsewhere and I think all they did was add a HALT PIN.
Friday 1st February 2013
I don''t believe the prossesor was a 6502C, the 6502 was 1MHz, the 6502A was 2MHz so an A variant would have been enough to run at 1.79MHz and I remember as a kid opening the computer I was looking for the 6502 processor and there is no chip inside with the part number 6502 $ the chip wasn''t numbered 6502 it had a different part number because I believe it was a modified 6502. from what I remember I don''t think there ever was a 6502C, a manufacturer did produce an 65C02 which was a lower power CMOS version but I am fairly sure didn''t come until some time later and was not used in the Atari computers.
Wednesday 30th January 2013
Dean ( United Kingdom)
600 / 800 XL
END OF PRODUCTION
BUILT IN LANGUAGE
1.79 (NTSC) / 1.77 (PAL) MHz
GTIA (video), POKEY (sound, I/O), ANTIC (video)
16 KB (600 XL up to 64 KB) / 64 KB (800 XL, expandable to 128 KB)
five text modes, max: 40 x 24, min: 20 x 12
16 graphic modes, maximum : 320 x 192
256 (16 colors with 16 intensities)
4 voices, 3.5 octaves
Composite video output, cartridge slot, peripheral port (SIO), parallel bus, 2 joystick plugs