Joseph Weisbecker

Lore & Background

Weisbecker began working with digital logic and computer systems in 1951, both professionally and as a hobby. His early work included a hobby tic-tac-toe computer built from relays in 1951, grade school educational aids using lights and switches in 1955, and the Think-a-Dot game in 1964. As a staff engineer at RCA, he performed advanced development research on LSI circuits and developed new product lines.

In 1970 and 1971, Weisbecker developed a new 8-bit architecture computer system, preceding Intel's 4004. He built a demonstration home computer called FRED (Flexible Recreational and Educational Device) using cassette tape storage and a television display. RCA released his work as the COSMAC 1801R and 1801U in 1975, and in 1976 the two ICs were integrated into the single-chip 1802. Between 1971 and the 1800 series production, he developed inexpensive application circuits including light guns, card readers, and cassette interfaces, some used in a demonstration microprocessor-based electronic game system that anticipated home video games.

Weisbecker designed the 1861 PIXIE graphics processor in 1975 as a minimal-cost video output chip. In 1975 he also developed the RCA Microtutor educational single-board computer and the production form of the RCA Studio II home video game system. In 1976 Popular Electronics published his design for the COSMAC Elf, a hobbyist computer. In 1977 articles added 1861-based video to the Elf. RCA released the COSMAC VIP in 1976, for which Weisbecker created the CHIP-8 interpreted programming language.

Reader's Guide

The COSMAC Elf continues to be a popular educational microcomputer construction project, with several newer designs based on it. The design principles of the 1802—a large, general-purpose register file and a limited set of instructions that execute in few cycles—presaged the RISC design philosophy, leading to the 1802 being called 'the grandfather of RISC'. The 1802's unique load mode, combined with RCA's radiation-hardened silicon on sapphire process, was instrumental in its selection for several space probes and space-based instruments, some of which are still working in their third decade in space. The 1802 is unique among first-generation processors in that it is still in production today, with its closest rival being the 8080A. CHIP-8 is still used by some communities, such as on graphing calculators like the TI-83 series, and has had interpreters created for many modern and older systems. Weisbecker later developed color graphic chips for a more advanced video game with expansion capabilities and a line of color graphic terminals, including products used in the Studio III.

Did You Know?

• Weisbecker's daughter Joyce Weisbecker became the first female video game designer using his CHIP-8 language.
• The 1802 processor has been called 'the grandfather of RISC' due to its design principles.
• The 1802 is still in production today, unique among first-generation processors.