CTIA/GTIA

## Description

CTIA ("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).

## Catalogue numbers

#### CTIA

    CO12295

#### GTIA

    CO14889 PAL
    CO14805 NTSC
    CO20120 SECAM

## Pinout

A0-A4 | address bus
D0-D7 | data bus
AN0-AN2 | ANTIC bus
Vcc | +5V power
T0-T3 | joystick trigger inputs
S0-S3 | console inputs
PAL | PAL clock input
CAD3 | color delay line adjustment input (sometimes called DEL)
COLOR | color signal output
LUM0-LUM3 | luminance signal output
CSYNC | composite sync output
/HALT | for synchronizing ANTIC & GTIA (when low and in HBLANK, pmg data on bus will follow)
Vss | Ground
OSC | main oscillator input
F0O | fast phase 0 output
Ø2 | phase 2 input
CS | chip select
R/W | read/write

Back (c) 1998-2004 Jindroush Last modified: Mon Feb 17 12:21:56 2003