This project implements an open source REU for the Commodore 64.
This is an updated version based on the final hardware design. The hardware consists of two PCBs. A Cyclone II development board uses an Intel EP2C5T144C8N FPGA and provides the FPGA and its configurator. A custom carrier board provides a mechanical and electrical interface for the FPGA board, a card edge connector compatible with the C64, logic level shifters required to convert between the C64 5V signals and the FPGA 3.3V signal levels, interfacing and power for the peripheral items on the PCB, a battery backed RTC, a 256 byte EEPROM, and a full-sized SD card socket.