Texas Instruments SN76489
The Texas Instruments SN76489, known as the Digital Complex Sound Generator (DCSG), is a programmable sound generator manufactured by Texas Instruments and released in 1979. It can generate audio in three pulse wave channels and a noise channel. Each channel's volume can be set from 0 to 15. The noise channel can run in either periodic noise or white noise mode. The chip appears to have been designed to match the capabilities of the popular General Instrument AY-3-8910, and, while popular through the 1980s, it never matched the ubiquity of the AY-3-8910. It is, however, a significant upgrade from Texas Instruments' previous PSG, the SN76477.
This chip saw various alternate packages and revisions. The original chip was sold in a narrow package (SN76489N), which saw a revision (SN76489AN). An alternate form was the SN76494 which could accept audio input through pin 9 which was unused in the original. This chip was sold in a narrow package (SN76494N) and had a revision (SN76494AN). Another variant form was the SN76496 which was used in the IBM PCjr. It also was released in a narrow package (SN76496N) with a revision (SN76496AN). The SN76496 was also cloned by NCR as the NCR 8496 and has been integrated into various chips for other platforms.
Personal
My cousin Brian had a Tandy 1000 on which we played a number of games which made use of this audio chip, in particular, games made by Sierra On-Line made great use of this chip. I also heard a little music from the Master System, then, when I got older and emulators matured, I enjoyed more music from the Master System and Game Gear. While I think capable music can be composed for the SN76489, the lack of a triangle wave makes bass impossible, so complex music is pretty limited, and attempts at bass result in a buzzy sound.
Media
Pictures
A Texas Instruments SN76489AN chip.
Documents
Manual - SN76489AN.
Manual - SN76494.
Pin out - SN76489.
Pin out - SN76494.
Pin out - SN76496.
Videos
Devices
In addition to scores of arcade cabinets, a number of computers, video game consoles, and sound cards used the SN76496 and its variants, including:
| Device | Release | Chips |
|---|---|---|
| Adam | 1983-10-?? | ? |
| ALF MC1 | 198?-??-?? | SN76489N x3 |
| BBC Master | 1986-??-?? | ? |
| BBC Micro | 1981-12-01 | SN76489AN |
| ColecoVision | 1982-08-?? | SN76489AN x1 |
| CreatiVision | 1981-??-?? | ? |
| Game Gear | 1990-10-06 | ? |
| Master System | 1986-06-?? | YM2602B VDP PSG |
| Mega Drive/Genesis | 1988-10-29 | YM7101 VDP PSG |
| Neo Geo Pocket | 1998-10-28 | ? |
| Neo Geo Pocket Color | 1999-03-16 | T6W28 SN76489-like clone |
| Nomad | 1995-10-?? | FF1004 (YM7101 VDP) PSG |
| IBM PCjr | 1984-03-?? | SN76496N x1 |
| Pico | 1993-06-26 | FC1001 (YM7101 VDP) PSG |
| Sega Mark III | 1985-??-?? | YM2602B VDP PSG |
| Sega SG-1000 | 1983-07-15 | SN76489AN |
| Sega SG-1000 II | 1984-??-?? | YM2217 VDP PSG |
| Sharp MZ-800 | 198?-??-?? | ? |
| Sord M5 | 1982-11-?? | ? |
| Tandy 1000 | 1984-11-?? | SN76496N x1 or NCR 8496 x1 or PSSJ-3 x1 |
| TI 99/8 | Unreleased (c. 1983) | SN76494N x1 |
| TNDY 3 Voice Sound Card | 2017-06-01 | SN76489AN x1 |
Songs
Some of my favorite songs which use the SN76489 include:
| Title | Game | Artist |
|---|---|---|
| Space Quest Theme | Space Quest I: The Sarien Encounter | Mark Crowe |
| Title Screen | Sylvan Tale | Saori Kobayashi |
Links
