Texas Instruments SN76477

SN76477 "complex sound generator" is a sound chip produced by Texas Instruments (TI). The chip came to market in 1978. A compatible version is identified as ICS76477.

The SN76477 was essentially a synthesizer on a chip, and was intended to be used with external controls like potentiometers and keyboards that would control the output. Many of its advanced features like envelope control required external circuity to implement. Moreover the internal model was based on the concept of one-shot sounds, in which a particular tone would be generated once for a specified time when triggered by an external signal, like a keypress.

The chip was used as a sound effects generator in arcade games and toys and for hobby projects. Among its better-known uses is the arcade game Space Invaders. More recently, it has been used as a hobbyist system for building simple analog synthesizers, using it with various external controllers.

In 1979, TI released the Texas Instruments SN76489, which had fewer features but was much easier to integrate into systems, and saw considerably wider use in the market.