Studio2600 for the Atari VCS (the original one)

Instructions

Move the joystick (cursor keys) around the grid to select tone (vertical axis) and frequency (horiziontal axis, values 0…31). Press the button (space bar) to play.

Use Select and Reset switches (F11, F12) to change the audio volume.

(Keyboard settings in the emulator may differ for locally saved presets. You may reset these by the “Help & Settings” menu [Controllers / Defaults] available by the gears icon at the bottom right corner of the emulation. You may emulate a steady rhythm by the turbo fire trigger, normally mapped to DEL, and adjust the BPM by its repeat frequency in the “Quick Options”.)

About

This is a tiny test application I wrote to explore sound on the Atari VCS / Atari 2600. The information provided by the Stella Programmer's Guide is a bit scarce:

TIA Registers AUDC0, AUDC1

HexD3D2D1D0Type of noise or division
00000set to 1
100014 bit poly
20010div 15 -> 4 bit poly
300115 bit poly -> 4 bit poly
40100div 2 : pure tone
50101div 2 : pure tone
60110div 31 : pure tone
701115 bit poly -> div 2
810009 bit poly (white noise)
910015 bit poly
A1010div 31 : pure tone
B1011set last 4 bits to 1
C1100div 6 : pure tone
D1101div 6 : pure tone
E1110div 93 : pure tone
F11115 bit poly div 6

So, here they are: All the sounds there are on the VCS, united on a funky screen, ready to be explored. Please mind that the frequences result from divisions of a base frequency and are not exactly chromatic tones. Moreover, some "sounds" (0, “set to 1”, and B, “set last 4 bits to 1”) are apparently just providing internal functionality and do not produce an audible noise or tone.

Downloads

Atari 2600 game ROM image files (4K):

The application (cartridge) has been developed as part of my project for RetroChallenge 2018/04.

This web pages uses an embedded version of the Javatari emulator by Paolo A. Peccin to run the NTSC version of "Studio2600" (by N. Landsteiner, 2018).

Norbert Landsteiner, www.masswerk.at,
April 2018.