The Development of a Satellite On-Board Microcomputer

Abstract

The paper describes a miniaturized computer for space use that is being developed under a contract from Intelsat. An all CMOS design is used with the corresponding low power and high speed associated with CMOS. Extensive use is made of LSI and the computer is based on the Intersil or Harris 6100 microprocessor. This has the same architecture as the PDP8-E and the extensive range of DEC PDP8-E software can be used. Provision has been made for both serial and parallel input/output ports. A development prototype is described that has serial and parallel ports. The associated memory is expansible up to 32K words in 2K blocks. RAM or PROM can be used or interchanged in blocks of 256 words. A programmable timer is included for real time applications. A bench model of the computer is also described which is made for program development. It is not to the same environmental standards as the development prototype but has the same facilities together with a control panel and provision for a teletype. The use of the Bench Model for software development is described.