DescriptionCTIA ("Color Television Interface Adapter") / GTIA ("George's Television Interface Adapter") is a television interface chip. ANTIC directly controls most of GTIA's operations, but the 6502 can be programmed to intercede and control some or all of GTIA's functions. GTIA converts the digital commands from ANTIC (or the 6502) into the signal that goes to the television. GTIA also adds some factors of its own, such as color values, player-missile graphics, and collision detection.
CTIA artifacts in blue/green, GTIA in 400/800 artifacts in green/blue and GTIA in XL/XEs artifacts in red/blue.
It's said that all PAL GTIAs are missing one red color, which is substituted by doubled brown color. Indeed, my tests show, that first color (#1) and last color (#15) are very similar or same.
Latest PAL GTIAs from China have annoying bug in 'GTIA modes', where some bits are displayed with high luminance. I have one report of such chip, it's production week is 9120 (end of May 1991).
CO14889 PAL CO14805 NTSC CO20120 SECAM