AY-3-8912
The compact cousin
A pin-reduced variant of the AY-3-8910 with identical sound capabilities, commonly found in the ZX Spectrum 128K and other space-constrained designs.
Overview
The AY-3-8912 is functionally identical to the AY-3-8910 but in a smaller 28-pin package with only one I/O port instead of two. This made it the chip of choice for the ZX Spectrum 128K where board space was at a premium.
Fast facts
- Sound: identical to AY-3-8910.
- Package: 28-pin DIP (vs 40-pin for 8910).
- I/O ports: 1 (vs 2 for 8910).
- Primary use: ZX Spectrum 128K, +2, +3.
Key difference
| Feature | AY-3-8910 | AY-3-8912 |
|---|---|---|
| Pin count | 40 | 28 |
| I/O Port A | Yes | Yes |
| I/O Port B | Yes | No |
| Sound quality | Identical | Identical |
| Registers | R0-R15 | R0-R15 (R15 unused) |
Why it matters
For game programmers, the distinction is largely irrelevant—the sound registers and capabilities are identical. The choice between 8910 and 8912 was a hardware design decision based on available board space and I/O requirements.
Family variants
The AY-3-8910 family covers three pin-counts plus a Yamaha clone:
| Chip | I/O | Pins | Notes |
|---|---|---|---|
| AY-3-8910 | A + B | 40 | Original — see AY-3-8910 |
| AY-3-8912 | A only | 28 | Spectrum 128K, CPC, Oric |
| AY-3-8913 | none | 24 | Bare — sound only, no I/O ports |
| YM2149F | A + B | 40 | Yamaha-made; software-compatible with finer envelope DAC |