Main Computer

The Main Computer is a low power single board computer with several specialized features. It was designed to be the control computer of the Gemini robot. It is a low power CMOS design with a 4 MHZ 8 bit Rockwell 6502 CPU.

It has a real time clock, 8 channel a/d converter, 5 serial ports, a parallel printer port, a bi-directional parallel port, 16 bit I/O ports, a hardware random number generator and a ROM monitor.

It also had four expansion slots that were similar to the slots of an Apple II computer. Some of the expansion boards for the Apple would also work in this computer.

A parallel interface board was also available. This board was designed to add an additional 16 I/O bits.

The schematics are available for free on thedownloadpage.

The main computer board.

A ROM expansion board was available that holds an additional 56K of bank switched ROM. These ROMs hold the Gemini "Life Mode Operating System" which includes a scheduler, voice command system, Robot BASIC programming language and an extensive vocabulary of compressed speech.

The ROM expansion board.

Processor R65C02, 4 MHZ
ROM Expansion 56K
Timer CDP-1878
Clock CDP-1879
A/D Converter ADC0317
Bit I/O 82C55 x 3
Parallel Port 65C21
Serial Controller 68C50

Michael Fowler 2016