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MOS keyboard encoders


The Signetics 2671 Programmable Keyboard and Communications Controller (PKCC) is a single MOS/LSI chip that combines the functionality of a single-chip keyboard controller and UART. This chip appears to be able to transmit keyboard input directly over serial, as well as transmit parallel data down a serial line, and received serial data to parallel.

The keyboard encoder portion supports both conductive and capacitive switches and is quad-mode with N-key rollover support. Rollover modes are N-key rollover with partial support for separate press and release codes (matrix row zero only, comprising the special keys 0xE0–EF, 0xF0–FF with shift), N-key rollover, two-key rollover (second key is signalled when the first key is released) and no rollover.

The term “programmable” here means that various characteristics can be configured at runtime. Output is either ASCII or matrix co-ordinates depending on how the device is set up.

MCU keyboard encoders

Little is known of microcontroller keyboard encoders manufactured by Signetics. Signetics may have provided or assisted with the keyboard encoder logic, or simply provided the chip manufacturing. Most examples are marked SCN8049H, which will be a licence-produced Intel 8049, part of their MCS-48 family. Those examples not marked as such still have the 1977 Intel copyright that would imply an MCS-48 chip and may also be SCN8049H.

Part number Date Additional codes Copyright Keyboard
QFJ4411 8805 CH5161C0027 Intel 1977 Chicony KB-5160C
2214F14 9122 Datacomp, C01K Intel 1977 Datacomp DFK192
2214J03 9122 V3, SCN8049H Intel 1977 Oriental Tech OK-100M
2216C18 9122 COPAM-8649B, SCN8049H Intel 1977 Copam K-457
2217716 9131 FDA-102/AE, SCN8049H Intel 1977 Forward FDA-102A
2223Q07 9215 MCL-5165; SCN8049H Intel 1977 Micronorth MCL-5165

The discovery of three separate brands of keyboard all with a Signetics chip dated 9122 seems unlikely but this is verified and not an error in the table.