Information AboutAntic |
| CATEGORIES ABOUT ANTIC | |
| graphics chips | |
| microprocessors | |
| atari 8-bit family | |
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ANTIC ('''''A'''lpha-'''N'''umeric '''T'''elevision '''I'''nterface '''C'''ircuit'') was an early video system chip used in the Atari 8-bit Family of Microcomputer s as well as some of Atari 's Video Game Console s of the 1980s . ANTIC was a Microprocessor dedicated to generating 2D Computer Graphics to be shown on a Television screen or Computer Display . It was a true microprocessor, in that it had an '' Instruction Set '' to run ''programs'' (called '' Display List s'') to process '' Data ''. The display list and the display data were written into RAM by a 6502 -compatible CPU . The ANTIC retrieved that information from RAM using a technique known as Direct Memory Access (DMA) . It processed the higher level instructions in the display list and translated these instructions into a real-time stream of simpler instructions to the CTIA Chip , a combination providing for 12 graphics modes. With the more advanced GTIA , 16 modes were available. ANTIC's most notable features were:
ANTIC had four types of instructions:
Each instruction had additional options by setting specific bits:
Although ANTIC was a microprocessor, its program counter was only 10-bits long. This meant the ''display list'' needed a JMP (Jump) instruction to cross a 1K boundary. A LMS (Load Memory Scan) was needed for data crossing a 4K boundary. Finally, a JVB (Jump on Vertical Blank) instruction was placed at the end of the ''display list''. The entire display had to equal 192 scan lines. EXTERNAL LINKS
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