- Expansion of main memory (SRAM) by 512KB,
- A 512KB Flash memory (EEPROM) for the firmware and frequently used programs,
- A mass storage device as a floppy disk replacement using modern SD cards (SD2IEC, µIEC) up to 2GB, and
- A real time clock (RTC) and a connector for the LCD display extension of the SD2IEC.
The FE3 can run any known VIC-20 software. Games and programs may be started using an easy to use menu. The FE3 gives any expected environment for any software and configures memory requirements automatically on startup.
In addition to the SRAM and EEPROM memory chips, the PCB contains an ATmega644/1284 microprocessor for the SD2IEC functionality, and an ATF1504 CPLD, which controls the hardware of the FE3 in a single chip.
The firmware of the FE3 is contained within the flash memory. It starts immediately after power on and when the VIC-20 is being reseted.
RAM Configuration: This menu option allows to configure any known memory configuration of the VIC-20.
Diskloader: This menu option exists to load and execute programs on SD card or floppy disk. The diskloader is freely configurable by the user and supports physical floppy disk drives as well as the integrated SD2IEC (µIEC).
Cartloader: This menu option exists to load and execute programs directly from flash memory. The flash provides 480KB (from 512KB) userspace. You can fill this userspace with most favourite games and programs. All kind of programs are possible (BASIC, programs, cartridges) to flash into userspace.
FE3 Wedge: This utility extends the command set of the VIC-20 and implements SJLOAD/SJSAVE (JiffyDOS compatible load and save). Because the integrated SD2IEC is also JiffyDOS compatible, it also benefits from the diskloader.
The schematic of the FE3 is available and the firmware is open source - if you can find them. Everyone can freely build a FE3 themselves. It is possible to build a FE3 on a breadboard or a 8 Bit Baby (see also Final Expansion v1)(link dead 2016-09-05).
Reverse engineered schematic from 10.1 board (accuracy not confirmed): Schematic (pdf, 55kB)