| Feature | KC89C72 | AY-3-8912 | Yamaha YM2149 | | :--- | :--- | :--- | :--- | | Technology | CMOS | NMOS | NMOS (but more common) | | Pin Count | 28 | 28 | 40 (or 28 in some variants) | | I/O Ports | None (pins N/A) | None (removed) | Two 8-bit ports | | Noise | Shared (w/ tone) | Same | Same (but different pol.) | | Supply Current | ~5 mA @ 2 MHz | ~30 mA | ~30 mA | | Availability | Scarce (vintage) | Rare | Widely available (eBay, etc.) | | Software Compatibility | 100% (AY-3-8910) | 100% | 99% (different mixer bit) |
Prices are highly variable. In one Chinese source, the chip is listed at around (approx. $0.80 USD), and in some cases, shipping is included . More commonly, specialized distributors require purchase of larger quantities or include higher per-unit pricing. For small quantities, eBay or individual sellers on Taobao may be the most accessible options. Some users also salvage KC89C72 chips from scrap slot machine and arcade game boards .
The internal structure of the KC89C72 can be broken down into specific operational modules. These modules process data written by a host CPU to generate complex audio waveforms, sound effects, or pseudo-random noise. kc89c72 datasheet
: Bus Control and Bus Direction signals used to manage data flow from a host CPU. DA0-DA7 : The 8-bit bidirectional data bus.
Although the original General Instrument chip is long out of production, the KC89C72 clone can sometimes still be found through specialized electronic component distributors. Typical sources include: | Feature | KC89C72 | AY-3-8912 | Yamaha
The chip uses a standard 40-pin DIP layout. While the official pinout diagram might be scarce, the KC89C72 is known to have pins that are function-compatible with the and Yamaha YM2149 . It can replace these chips in existing circuits without hardware modification.
Are you designing a new , or are you using this chip to repair an existing vintage retro-computer board? Let me know your exact use case so I can generate corresponding schematic diagrams or functional code snippets. Share public link The internal structure of the KC89C72 can be
No Connection (or internal connection depending on die variant) Analog Channel B Audio Output for Channel B 4 Analog Channel A Audio Output for Channel A 5 No Connection 6 I/O Port B, Bit 7 7 I/O Port B, Bit 6 8 I/O Port B, Bit 5 9 I/O Port B, Bit 4 10 I/O Port B, Bit 3 11 I/O Port B, Bit 2 12 I/O Port B, Bit 1 13 I/O Port B, Bit 0 14 I/O Port A, Bit 7 15 I/O Port A, Bit 6 16 I/O Port A, Bit 5 17 I/O Port A, Bit 4 18 I/O Port A, Bit 3 19 I/O Port A, Bit 2 20 I/O Port A, Bit 1 21 I/O Port A, Bit 0 22 Master timing input (1 - 2 MHz square wave) 23 Internal testing pin (leave disconnected) 24 Chip Select (active low) 25 Bus Control 2 26 Main 5V Power Supply Input 27 Bus Direction Control Line 28 Bus Control 1 29 Control configuration pin 30 Bidirectional Data Bus, Bit 7 31 Bidirectional Data Bus, Bit 6 32 Bidirectional Data Bus, Bit 5 33 Bidirectional Data Bus, Bit 4 34 Bidirectional Data Bus, Bit 3 35 Bidirectional Data Bus, Bit 2 36 Bidirectional Data Bus, Bit 1 37 Bidirectional Data Bus, Bit 0 38 Analog Channel C Audio Output for Channel C 39 Internal testing pin (leave disconnected) 40 Master System Reset (Active Low) 3. Internal Architecture & Register Map
The Ultimate Guide to the KC89C72 Microcontroller: Datasheet Breakdown, Architecture, and Applications