RETRO Innovations

Introduction

C=Key bridges the gap between Commodore and PC keyboard operation!

Depending on configuration, C=Key offers VIC-20, C64, C64C, SX64, C128, C128D, and C128DCR owners the ability to either use their CBM keyboard with a PS/2 supported PC, or utilize a PS/2 keyboard on their Commodore machine.  In either usage, multiple keyboard mappings are supported, to handle keyboard differences and application preferences.  No drivers or programming are required for operation.

Options

C=Key can be purchased in the following configurations:

• PCB Only: Bare circuit board
• PCB + uC: PCB and programmed Atmel ATMEGA162, used for connecting CBM KB to PC (includes uC Crystal and trimming capacitors)
• PCB + uC + Crosspoint Switch: Allows either configuration
• Preconfigured kits for specific CBM models.

Additional options include:

• dual joystick connectors can be added, to allow CBM joystick operation on the PC.
• Any kit can be ordered pre-assembled (please allow additional handling time)

Requirements

• A PS/2 compatible keyboard (USB keyboards with PS/2 converters may not work) with a Mini-DIN6 plug.
• One of the following machines:

• VIC-20, C64, C64C
• SX64
• C128
• C128D/C128DCR
• For the SX64/C128D/C128DCR operation with a PS/2 keyboard, a DB25M to DB25M cable is also required.

Purchase

C=Key models can be purchased at the RETRO Innovations Online Store.

Image Gallery

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Technical Details

C=Key consists of an Atmel ATMEGA162 microcontroller in DIP format and an optional Mitel/Zarlink MT8812 crosspoint switch.  In “host” mode, the system reads data from the PS/2 keyboard and emulates the Commodore switch matrix with the crosspoint switch.  In “device” mode, the system scans the Commodore keyboard matrix 60 times a second, converting keypresses into PS/2 compliant scan codes.  GPLv2 licensed C firmware source code can be modified to support nearly any matrix-style keyboard configuration.

Firmware features include:

• Multiple key rollover support
• Configurable keyboard matrix scanner supports 1×1 to 16×8 matrices (hardware supports a maximum of 12×8 matrices)
• Single IC solution (for matrix keyboard to PC configuration)
• Key repeat functionality supported and PS/2 keyboard compliant

The PCB features include:

• A single PCB for VIC/64/128/SX64
• Support for dual joysticks for emulator use.
• Through hole design makes “do-it-yourself” construction easy.

Support

Bill of Materials

Assembly Details

Operation

1. C

Configuration

OLD STUFF

View some pictures or download the code and schematic

• Any kit can be ordered pre-assembled (please allow additional handling time)