# Texas Instruments SN76489

> programmable sound generator chip

**Wikidata**: [Q2708134](https://www.wikidata.org/wiki/Q2708134)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Texas_Instruments_SN76489)  
**Source**: https://4ort.xyz/entity/texas-instruments-sn76489

## Summary
The Texas Instruments SN76489 is a programmable sound generator chip introduced in 1979. Manufactured by Texas Instruments, this integrated circuit is capable of generating audio signals built from basic waveforms and was widely utilized in early home computers and gaming consoles.

## Key Facts
- **Inception:** 1979
- **Manufacturer:** Texas Instruments
- **Classification:** Programmable Sound Generator (PSG), Sound Chip, Integrated Circuit Model
- **Aliases:** Digital Complex Sound Generator (DCSG), SN76489A, SN76489AN, SN76494, SN76496, Sound Generation Controller (SGC)
- **Notable Systems Used In:** Texas Instruments TI-99/4A, Sega Genesis, ColecoVision, Coleco Adam, SG-1000, IBM PCjr, BBC Micro, and BBC Master.
- **Comparison:** Distinct from the General Instrument AY-3-8910.
- **Interface:** Features an 8-pin data interface (D0–D7) along with control pins (READY, WE, OE) and audio output (SND OUT).

## FAQs
### Q: What devices used the Texas Instruments SN76489?
A: The chip was used in a variety of classic computing and gaming platforms, including the Texas Instruments TI-99/4A, Sega Genesis, ColecoVision, IBM PCjr, SG-1000, BBC Micro, and the Coleco Adam.

### Q: What type of sound chip is the SN76489?
A: It is a Programmable Sound Generator (PSG), also known as a Digital Complex Sound Generator (DCSG). It functions as an integrated circuit that generates audio by combining basic waveforms.

### Q: Is the SN76489 the same as the General Instrument AY-3-8910?
A: No, while both are programmable sound generators used in similar eras, the Texas Instruments SN76489 is listed as being different from the General Instrument AY-3-8910.

## Why It Matters
The Texas Instruments SN76489 played a pivotal role in defining the audio landscape of the early 1980s home computer and video game market. As a dedicated programmable sound generator, it offloaded audio processing from the main CPU, allowing for more complex game logic and smoother performance while providing distinct, recognizable synthetic audio. Its inclusion in influential platforms like the TI-99/4A, the ColecoVision, and the Sega Genesis (often working in tandem with other chips) cemented its place in hardware history. By providing a standardized method for audio generation across multiple third-party platforms, the SN76489 helped establish the sound aesthetic of the 8-bit and early 16-bit eras. Its design, classified under the "Digital Complex Sound Generator" alias, represents a significant step in the evolution of dedicated multimedia silicon.

## Notable For
- **Broad Industry Adoption:** Unlike many chips restricted to a single brand, the SN76489 was utilized by diverse manufacturers including Sega, Coleco, IBM, and the BBC.
- **Longevity:** First released in 1979, its variants (such as the SN76496) continued to be used in consoles like the Sega Genesis well into the late 1980s and early 1990s.
- **Alias Variety:** Known by several technical names including "Sound Generation Controller" and "Digital Complex Sound Generator," reflecting its versatile application in system architectures.
- **Distinct Architecture:** It is explicitly categorized as different from its primary contemporary competitor, the General Instrument AY-3-8910.

## Body
### Technical Classification
The Texas Instruments SN76489 is an integrated circuit model classified as a **Programmable Sound Generator (PSG)**. It is designed to generate audio signals built from one or more basic waveforms. In technical documentation and system schematics, it is often referred to as a **Digital Complex Sound Generator (DCSG)** or **Sound Generation Controller**.

### Hardware Integration and Usage
The chip saw extensive use across the computing and gaming industries. It was a primary audio component for the **Texas Instruments TI-99/4A** home computer. Beyond its creator's own hardware, it was adopted by:
- **Sega:** Used in the SG-1000 and the Sega Genesis.
- **Coleco:** Featured in the ColecoVision and the Coleco Adam.
- **IBM:** Utilized in the IBM PCjr.
- **Acorn Computers:** Present in the BBC Micro and BBC Master.

### Pinout and Interface
The SN76489 typically utilizes a specific pin configuration for data and control. Based on the available schematic data, the pinout includes:
- **Data Pins:** D0 through D7 (D5, D6, D7 occupy pins 1, 2, 3 respectively; D0 occupies pin 10).
- **Control Pins:** READY (Pin 4), WE (Write Enable, Pin 5), OE (Output Enable, Pin 6).
- **Audio Output:** SND OUT (Pin 7).
- **Power/Ground:** GND (Pin 8) and NC (No Connect, Pin 9).

### Variants
The SN76489 line includes several hardware variants with specific designations, including:
- SN76489A
- SN76489AN
- SN76494
- SN76496 (also referred to as the Texas Instruments SN76496)

### Manufacturer
The chip was designed and manufactured by **Texas Instruments**, an American multinational semiconductor company founded in 1930.

## References

1. Freebase Data Dumps. 2013