Texas Instruments SN76477

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The TI SN76477 Sn76477.jpg
The TI SN76477

SN76477 "complex sound generator" is a sound chip produced by Texas Instruments (TI). The chip came to market in 1978, [1] and TI ceased production of the part.[ when? ] A compatible version is identified as ICS76477. [2] The chip is typically used as a sound effects generator in arcade games and toys and for hobby projects. The use of the SN76477 in a musical context is limited by the fact that it was difficult to electronically control the pitch of the produced sound. [3]

Contents

Overview

The following quotation summarizes its facilities:

[T]he SN76477 generates complex audio signal waveforms by combining the outputs of a low frequency oscillator, variable frequency (voltage controlled) oscillator (VCO) and noise source, modulating the resulting composite signal with a selected envelope and, finally, adjusting the signal's attack and decay periods. At each stage, the process can be controlled at the programming inputs of the signal modification and generation circuits, using control voltages, logic levels, or different resistor and capacitor values.

Lou Garner, Solid State, Popular Electronics magazine, October 1978. [4]

There were two different sizes of the SN76477 available. The SN76477N was in a standard 0.6 in (15.24 mm) width dual in-line package (DIP). The SN76477NF was in a less common 0.4 inch (10.16 mm) width DIP.

SN76477 top view SN76477 TOP VIEW.png
SN76477 top view
A redraw of a demonstration circuit used to try out most of the capabilities of the 76477 sound chip 76477 Demo Circuit-D.png
A redraw of a demonstration circuit used to try out most of the capabilities of the 76477 sound chip

The text below is intended to explain the use of the 76477 in the demo circuit shown at the right.

The Texas Instruments SN76488 "complex sound generator" is a sound chip produced by Texas Instruments, similar to the Texas Instruments SN76477 but with internal audio amplifier.

Redraws of 76477 application circuits;

Uses

Uses of the SN76477 include the following devices:

See also

References

  1. Type SN76477 Complex Sound Generator Archived 2009-10-07 at the Wayback Machine – Texas Instruments Bulletin No. DL-S 12612, July 1978, (The datasheet)
  2. BG-Micro lists ICS76477 Sound Generator. Archived 2010-02-13 at the Wayback Machine
  3. SN-Voice: discussion of the SN Voice synthesiser. Archived 2008-06-29 at the Wayback Machine
  4. Solid State, Popular Electronics Magazine, October 1978.
  5. 8080a Simulation: Space Invaders – a report on writing an emulator for Space Invaders.