Central Air Data Computer
The Central Air Data Computer is the integrated flight control system used in the early versions of the US Navy's F-14 Tomcat fighter. It is notable for its use of a MOS-based LSI chipset, the MP944, arguably making the first microprocessor design in history.
The CADC was designed and built at Garrett AiResearch by a team lead by Steve Geller and Ray Holt, and supported by the startup American Microsystems. Design work started in 1968 and was completed in 1970, beating out a number of electromechanical systems that had also been designed for the F-14.
The CADC as a whole consisted of a 20-bit A to D convertor, several quartz pressure sensors to detect the positions of various switches and flight controls, and the MOS-based CPU. Inputs to the system included the primary flight controls, a number of switches, static and dynamic air pressure (for calculating stall points and aircraft speed) and a temperature gauge. The outputs controlled the primary fight controls, wing sweep, the F-14's leading edge "glove", and the flaps.
The MP944 consisted of six chips, used in various numbers to build the CADC's CPU. They were the Parallel Multiplier Unit (PMU), the Parallel Divider Unit (PDU), the Random Access Storage (RAS), the Read Only Memory (ROM), the Special Logic Function (SLF), and the Steering Logic Unit (SLU). The complete microprocessor system used 1-PMU, 1-PDU, 1-SLF, 3-RAS's, 2-SLU's, and 19-ROM's.
Holt wrote a "whitepaper" introduction to the design in 1971, but the Navy classified it. Another attempt in 1985 also failed, and it was not until 1997 that they finally agreed to allow it to be published. For this reason it remains fairly unknown in spite of its historical importance. Holt went on to found Microcomputer Associates and produce several single-chip systems based on the general principles of the MP944.