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Introduction to Microcontrollers:
Microcontroller History

In 1968, Garrett AiResearch received the challenge to design a digital computer for the US Navy’s F14 Tomcat fighters. The digital computer was called "Central Air Data Computer" (CADC). The design was complete by 1970, and used a MOS-based chipset as the core CPU named MP944 . It was "a 20-bit, pipelined, parallel multi-microprocessor" that was 20 times smaller and more reliable than its competitor: an electromechanical system then under development for the main flight control computer. The design was considered so advanced that the Navy decided to keep it secret until 1997.

About the same time, two commercial microprocessors were delivered: Intel 4004 and Texas Instruments TMS 1000. In September 1973, TI received the patent for the single chip microprocessor.

The 4004 was later followed in 1972 by the 8008, the world’s first 8 bit microprocessor. These processors are the precursors to the very successful Intel 8080 (1974) and Zilog Z80 (1976).

The first Motorola 6800 was released in August 1974.

In 1975, after resigning from Motorola, the engineering team that was designing the 6800 was introducing the 6502 priced at 25$ at the Westcon show (the Motorola 6800 and Intel 8080 were selling at the same show for 179$).

A major advance over its predecessors was the Motorola 6809 (introduced in 1978), one of the most powerful, orthogonal, and clean 8-bit microprocessor designs ever fielded.

In 1982, Western Design Center introduced an upgraded CMOS version of the popular NMOS-based MOS Technology 6502.

The first single-chip 16-bit microprocessor was the TI's TMS 9900. The chip was packaged in a large ceramic 64-pin DIP package, while most 8-bit microprocessors such as the Intel 8080 used the more common, smaller, and less expensive plastic 40-pin DIP. A follow-on chip, the TMS 9980, was designed to compete with the Intel 8080, had the full TI 990 16-bit instruction set, used a plastic 40-pin package, moved data 8 bits at a time, but could only address 16 KB.

In 1984, Western Design Center introduced the CMOS 65816 16-bit upgrade of the 65C02.

Today, about 55% of all CPUs sold in the world are 8-bit microcontrollers. According to SEMICO, over 4 billion 8-bit microcontrollers were sold in 2006.

A typical home in a developed country is likely to have only four general-purpose microprocessors but around three dozen microcontrollers. A typical mid range automobile has as many as 30 or more microcontrollers.

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