Television Interface Adaptor
|Television Interface Adaptor|
1.) Pulse Wave or Noise
The Television Interface Adaptor (TIA) is the custom interface chip Atari designed for the Atari 2600 to display graphics, read joystick input, and produce sound. The chip's primary designer, Jay Miner, went on to design the main circuitry of the Atari 8-bit and Commodore Amiga 16-bit home computers.
Graphics and music are difficult to make on the TIA. Few pitches are available, many of which are atonal.
On each of two channels, you can choose:
- Waveform: 50% or 58% pulse wave, 4 other waves, or white noise.
- Pitch: Range dependent on waveform.
- Volume from 0 to 15.
Due to the limited capabilities of TIA chip and the adolescence of video game composition, the full-length tacks while standard for the modern video games were incredibly rare for Atari 2600 games. Mostly music was done in a form of short jingles, and a large part of the ones having a rarer longer looping form were still under 30 seconds.
The TIA can produce PCM music, but it takes a lot of RAM (while Atari 2600 doesn't have much), usually forcing developers to use it with static images or completely black screen. It seems there weren't any official games to ever utilize the PCM music or speech.
There is at least one homebrew game, Stella's Stocking (A26), that does it. Here are some notes from the game's composer how it was created. For some speech synthesis in few of other Atari 2600 games (but not for the music), AtariVox has been used.
Due to the numerous redesigns of Atari hardware, the TIA chip is located in different locations on various boards, and has different chip designations.
The TIA was originally designed for the 2600, but was later used in the 7800 for backward compatibility.
Pretty much every game released for the Atari 2600 or 7800 utilizes the TIA for sound.
Any Atari 2600 or 7800 emulator with sound capabilities emulates the TIA.