The SN76489 is a TTL compatible, 4 channel Programmable Sound Generator (PSG) IC from Texas Instruments. It's main application has been entertainment and it has been used to provide music and sound effects in games consoles, arcade hardware and home computers.
Features of the SN76489 are:
- Three square wave, programmable tone generators
- One programmable white noise generator
- Programmable attenuation
- Mono audio output
The SN76489 is included 'on-chip' in SEGA's Video Display Processors (VDP) for their Master System, Game Gear, and Megadrive (Sega Genesis in North America), game consoles. The SEGA VDP is in fact based on the Texas Instruments TMS9918 VDP.