Zilog manufactured a number of models of “Keyboard Controller”, trademarked as KBC™. These chips are part of their Z8 microcontroller family. The Zilog literature does not state whether these chips are intended to be used as keyboard controllers or as microcontroller-based keyboard encoders. Brief summaries exist for these models but no datasheets have been found. It would appear that Zilog intended for the customer to supply the software to run on the controller.
Zilog appear to have made little effort to clearly differentiate between their keyboard controller models. The different models each have a 124 × 8-bit register file, presumably intended to retain the key state across the set of registers. 8 bits per key would for example allow you to track the key’s active/inactive state across multiple scanning cycles.
The documented models are as follows:
|Z08602||NMOS Z8 8-bit MCU||Zilog 1997 Master Selection Guide|
Part Z0860204PSC has been found in a number of keyboards. These microcontroller-based keyboard encoders also appear to be part of Zilog’s 8 microcontroller family and may share the same hardware as their “keyboard controllers”. Known examples include:
|Z0860204PSC||Lion Tech DS-2006||R723||9252|
|Forward Electronics FDA-102D||1013||9521|
Determination of which code printed onto the chip is the ROM code identifier is only a guess.